PubMed Health⌕ Search

Biomedical subjects

H C Herrmann

Publications and source records attributed to H C Herrmann.

At least 55 records · Page 3Linked to original sources
PubMed1994

Technique of percutaneous transvenous mitral commissurotomy using the Inoue balloon catheter.

Percutaneous transvenous mitral commissurotomy (PTMC) with the Inoue balloon has had increasing use internationally since its introduction in 1984. This device was designed specifically for mitral commissurotomy and differs substantially from conventional large diameter peripheral arterial or valvuloplasty balloon catheters. It is constructed of two layers of latex with a nylon mesh in between. The latex is extremely compliant, whereas the nylon mesh limits the maximum inflated diameter of the balloon and also gives it a unique shape and set of inflation characteristics. The balloon inflates in three stages. The front half inflates first, creating the appearance of a balloon flotation catheter. The proximal half of the balloon inflates next, creating an hourglass shape. When straddling across the valve, this allows self-positioning of the balloon. Finally, the center portion inflates, resulting in commissurotomy. The technique of commissurotomy involves introducing the balloon into the left atrium over a guidewire and then passing it into the left ventricle with the distal portion of the balloon inflated in a manner analogous to crossing the tricuspid valve with a pulmonary artery flotation catheter. Thus a guidewire is not used to enter the left ventricle with this technique. Increasing inflation volumes allow a single balloon catheter to be inflated to a variety of sizes, allowing stepwise dilatation of the mitral valve in a manner analogous to coronary angioplasty. This report describes the performance of this technique in detail, with practical approaches to many common problems encountered during PTMC.

Angioplasty, Balloon↗
PubMed1994

Acute and chronic efficacy of percutaneous transvenous mitral commissurotomy: implications for patient selection.

Despite the introduction of penicillin and improvements in the standard of living and delivery of primary health care, rheumatic mitral stenosis remains an important medical problem in the United States as well as abroad. In the past decade, percutaneous transvenous mitral commissurotomy (PTMC) with the Inoue balloon catheter has emerged as a safe and efficient treatment for symptomatic patients and has supplanted surgical commissurotomy as the initial treatment approach in the majority of patients with mitral stenosis. Acutely, balloon valvuloplasty can achieve an approximately 100% increase in mitral valve area and markedly improve symptoms, including dyspnea and NYHA functional class. However, peak oxygen consumption during exercise may not increase acutely, and the subjective improvement in dyspnea is likely related to a diminished work of breathing. Chronically, the hemodynamic improvements achieved with PTMC are maintained (up to 5 yr) with a low rate of recurrent symptoms due to restenosis, production, or progression of mitral regurgitation or inadequate initial dilation. Freedom from death, mitral valve replacement, and repeat valvuloplasty range between 51% and 84% at 4-5 yr postprocedure, depending on various selection criteria. Functional improvement, as measured by exercise capacity with respiratory gas analysis, occurs over several months suggesting that chronic peripheral alterations in the skeletal muscle and vasculature of patients with long-standing mitral stenosis may limit the initial benefit of successful PTMC until vascular remodeling or aerobic training can allow the skeletal musculature to use the greater cardiac output afforded by successful PTMC. Careful patient selection is essential to obtain the best hemodynamic improvement with the lowest rate of complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Catheterization↗
PubMed1993

Comparison of results of percutaneous balloon valvuloplasty in patients with mild and moderate mitral stenosis to those with severe mitral stenosis. The North American Inoue Balloon Investigators.

Most reported studies of percutaneous balloon valvuloplasty in adults with acquired mitral stenosis have used patients with severely stenosed valves. The risks and benefits of valvuloplasty were examined in a multicenter registry of patients to determine whether balloon valvuloplasty can effectively dilate less severely obstructed valves, and to clarify the role of this procedure in symptomatic patients with mild and moderate mitral stenosis. The study groups were derived from the North American Inoue Balloon Valvuloplasty Registry. Full hemodynamic data were available in 264 patients; 45 (17%) with mild or moderate mitral stenosis (mitral valve area > or = 1.3 cm2) were compared with the remaining 219 with severe mitral stenosis (valve area < 1.3 cm2). Percutaneous balloon valvuloplasty was performed using the anterograde transseptal technique with an Inoue balloon. The mean age of patients with mild and moderate mitral stenosis was 53 +/- 13 years, and all were symptomatic with a mean New York Heart Association functional class of 2.9 +/- 0.7. Balloon valvuloplasty resulted in an increase in calculated mitral valve area from 1.4 +/- 0.1 to 2.3 +/- 0.7 cm2 (p < 0.05), and a final valve area > or = 1.9 cm2 was achieved in 37 patients (82%). There were no procedural deaths, but complications included right atrial perforation, transient ischemic attack and emergency surgery for severe mitral regurgitation. One-year follow-up evaluation revealed symptomatic improvement in most patients (mean New York Heart Association class 1.4 +/- 0.6; p < 0.0001). However, 2 patients needed repeat valvuloplasty for restenosis, and 5 had mitral valve replacements.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Effect of balloon mitral valvuloplasty on exercise capacity, ventilation and skeletal muscle oxygenation.

OBJECTIVES: The short- and long-term effects of valvuloplasty on exercise capacity, ventilation and skeletal muscle oxygenation were investigated to determine whether a dissociation between hemodynamic improvement and exercise capacity occurs in patients with mitral stenosis. BACKGROUND: Percutaneous balloon mitral valvuloplasty in patients with mitral stenosis results in immediate hemodynamic improvement at rest and with exercise. Improved exercise capacity has been described at 3 months after valvuloplasty. In patients with left ventricular dysfunction, acute therapeutic interventions that produce hemodynamic benefit do not immediately improve exercise capacity. METHODS: Maximal bicycle exercise with measurement of respiratory gases was performed in 11 patients with mitral stenosis before and at 48 h and 3 months after successful percutaneous balloon mitral valvuloplasty. Respiratory and leg skeletal muscle oxygenation were assessed by monitoring changes in light absorption of the serratus anterior and vastus lateralis muscles using near-infrared spectroscopy and were expressed as percent deoxygenation. RESULTS: Mitral valvuloplasty significantly increased mean mitral valve area from 1.0 +/- 0.2 to 1.7 +/- 0.3 cm2 (p < 0.05). Immediately after valvuloplasty, peak exercise oxygen consumption (VO2), VO2 at the anaerobic threshold, ventilation, peak respiratory and leg muscle deoxygenation all remained unchanged. At submaximal work loads, respiratory muscle deoxygenation was attenuated (25 W: before 12 +/- 4%; 48 h 4 +/- 3%; 50 W: before 10 +/- 5%; 48 h 5 +/- 4%; both p < 0.05). At 3 months, significant improvement in peak VO2 (before 10.9 +/- 5%; 3 months 14.6 +/- 6.2 ml/kg per min; p < 0.05) and VO2 at the anaerobic threshold (before 7.1 +/- 2.4; 3 months 8.4 +/- 2.3; p < 0.05) were observed, whereas ventilation remained unchanged. No further improvement was seen in respiratory muscle deoxygenation. Vastus lateralis deoxygenation at submaximal work loads tended to be decreased. CONCLUSIONS: Long-term changes in skeletal muscle and the lungs preclude immediate enhancement of exercise performance after balloon mitral valvuloplasty. Immediate symptomatic improvement probably results from an immediate decrease in the work of breathing. Long-term symptomatic improvement results from changes that occur in the peripheral skeletal musculature as well as from the reduced work of breathing.

Adult↗
PubMed1993

Effect of balloon size and stepwise inflation technique on the acute results of Inoue mitral commissurotomy. Inoue Balloon Catheter Investigators.

Currently percutaneous transvenous mitral commissurotomy (PTMC) is performed by most operators using stepwise inflation of the Inoue balloon beginning at a small diameter and increasing size by a sequence of inflations to nominal diameter. The effect of balloon size on procedure results using the Inoue balloon has not been evaluated. In 260 patients final balloon inflation was to nominal size in 42% of pts, larger than nominal size (overinflated) in 10%, and less than nominal size (underinflated) in 48% of pts. The average number of inflations was 3 (range 1-9). Pressure gradient and Doppler mitral regurgitation (MR) were assessed after each inflation. When MR increased, further inflations were not done. Patients in whom the balloon was overinflated underwent more balloon inflations than those in whom it was inflated to nominal size (5.0 +/- 2.1 vs. 2.9 +/- 1.4, p < 0.01). Those with balloon underinflation had fewer balloon inflations (2.4 +/- 1.2 vs. 2.9 +/- 1.4, p < 0.01). The post PTMC valve area in patients with overinflation was slightly less than those with nominal inflations (1.6 +/- 0.4 vs. 1.8 +/- 0.7), and with underinflation the valve area was no different compared to nominal inflation. Using a stepwise procedure, if mitral regurgitation was noted to increase after a balloon inflation, the procedure would be stopped even if less than an ideal result was achieved. Fewer inflations were done in patients in whom the balloon was inflated to less than nominal size because of the appearance of mitral regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Calibration↗
PubMed1993

Long-term outcome of enoximone therapy in patients with refractory heart failure.

Few options are available for patients with severe heart failure that is unresponsive to therapy with digoxin, diuretics, and vasodilators. The clinical responses and predictors of survival were studied in 41 consecutive patients with New York Heart Association (NYHA) class IV heart failure during long-term oral enoximone therapy (mean dose 232 +/- 15 mg/day). The mean age was 60 +/- 1 years, and the initial left ventricular ejection fraction was 0.19 +/- 0.01. The cause of heart failure was either coronary artery disease (n = 23) or dilated cardiomyopathy (n = 18). Symptomatic improvement occurred in the majority (83%) of patients; 24% improved two or more NYHA classes. Although the 12-month mortality rate for the entire group was high (54 +/- 8%), a subgroup of patients with dilated cardiomyopathy achieved a sustained benefit with a decrease in symptoms > 1 NYHA class, fewer hospitalizations, and a survival rate at 24 months of 60%. Multivariate analysis identified the cause of heart failure, left ventricular ejection fraction, and clinical improvement within 60 days of enoximone therapy as predictors of a favorable long-term outcome. The presence of coronary artery disease was most predictive of early mortality (p < 0.0002), with only 5% of patients surviving > 18 months compared to 66% of those with dilated cardiomyopathy. Median survival rates were 132 +/- 31 and 921 +/- 214 days (p < 0.001) for the coronary artery disease and dilated cardiomyopathy populations, respectively. Oral enoximone can provide symptomatic improvement and a palliative option for the majority of patients with refractory heart failure resulting from cardiomyopathy.

Cardiomyopathy, Dilated↗
PubMed1993

Intravascular ultrasonographic assessment of the results of coronary artery stenting.

We studied 12 patients undergoing elective coronary stent implantation for either recurrent restenosis or adverse lesion appearance. By use of a 4.8F 20 MHz intravascular ultrasound catheter, the conventional angioplasty site was examined before and after coronary stent implantation. Quantitative angiographic analysis revealed the expected excellent final result with a group mean poststent diameter reduction of 14 +/- 9% and a cross-sectional area reduction of 22 +/- 13%. Angiographic analysis also indicated an increase in minimum stenosis diameter from 1.8 +/- 0.6 mm after conventional balloon angioplasty to 2.8 +/- 0.3 mm after coronary stent implantation. Quantitative analysis of the corresponding intravascular ultrasound images, however, revealed significant residual endoluminal obstruction. Fractional plaque area remained unchanged from 30 +/- 12% after conventional balloon angioplasty to 32 +/- 11% after stent implantation. The circumferential distribution of plaque increased significantly from 0.44 +/- 0.17 to 0.55 +/- 0.15 (p = 0.03) after stent implantation. Despite the lack of significant change in the ultrasound-determined minimum stenosis diameter after stent placement, there was a borderline significant increase in the plaque-free lumen area (before stent, 6.35 +/- 1.55 mm2; after stent, 7.25 +/- 1.6 mm2; p = 0.06). Thus, in contrast to the substantial improvement in the angiographically assessed residual luminal obstruction after stent implantation compared with the prestent condition, considerably less improvement was found by intravascular ultrasound-assessed examination. Morphometric analysis indicated a tendency toward circumferential remodeling of plaque. The inherently different approaches to vascular imaging represented by contrast angiography and intravascular ultrasound techniques appear to provide complementary information.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Angiography↗
PubMed1993

Mechanisms and outcome of severe mitral regurgitation after Inoue balloon valvuloplasty. North American Inoue Balloon Investigators.

OBJECTIVES: The purpose of this study was to assess the incidence, mechanism and outcome of severe mitral regurgitation after treatment of mitral stenosis with percutaneous mitral valvuloplasty using the Inoue balloon. BACKGROUND: Severe mitral regurgitation occurs in up to 15% of percutaneous balloon valvuloplasty procedures for acquired mitral stenosis. The incidence and mechanism of production of mitral regurgitation with the recently introduced single-balloon Inoue technique have not been characterized. METHODS: We examined the incidence, mechanism, predictors and outcome of severe mitral regurgitation after Inoue balloon valvuloplasty in 280 patients in the North American multicenter registry. Twenty-one patients who developed either clinically significant or angiographically severe regurgitation were identified, and their echocardiograms were reviewed to determine the mechanism of regurgitation. These patients were then compared with the remaining patients without severe regurgitation to identify predictors of this outcome. RESULTS: The incidence of severe regurgitation in this study was 7.5%, and the mean grade of angiographic regurgitation in these patients increased from 0.9 +/- 1.0 to 2.8 +/- 0.7 (p < 0.05). The most common cause of regurgitation (43%) was rupture of chordae tendineae to the anterior or posterior mitral leaflet. Tearing of a leaflet (usually the posterior one) occurred in 30% of patients; and no recognizable structural abnormality, with wide splitting of the commissures and a central regurgitant jet, was present in five patients (26%). All patients with definite posterior leaflet tears had heavily calcified leaflets. Patients who developed severe regurgitation had fewer balloon inflations and a higher grade of preexisting mitral regurgitation but were otherwise similar to the remaining patients without severe regurgitation. During 6-month follow-up, 71% of the patients with severe regurgitation were treated surgically; the grade of regurgitation decreased in four patients (19%), and five patients (24%) have not required mitral valve replacement during 18 +/- 5 months of follow-up. CONCLUSIONS: Severe mitral regurgitation is a relatively infrequent complication of Inoue balloon valvuloplasty and results from disruption of the valve integrity, including chordal rupture and leaflet tearing. Careful balloon positioning may help avoid chordal rupture, and heavily calcified posterior leaflets may be at greater risk of tearing. Most patients who develop severe regurgitation will require nonemergency mitral valve replacement.

Adult↗
PubMed1993

Percutaneous balloon pericardiotomy for the treatment of cardiac tamponade and large pericardial effusions: description of technique and report of the first 50 cases.

OBJECTIVES: This study describes the technique, clinical characteristics and results of the first 50 patients undergoing percutaneous balloon pericardiotomy as part of a multicenter registry. BACKGROUND: Percutaneous balloon pericardiotomy involves the use of a percutaneous balloon dilating catheter to create a nonsurgical pericardial window. METHODS: Patients eligible for percutaneous balloon pericardiotomy had either cardiac tamponade (n = 36) or a moderate to large pericardial effusion (n = 14). In addition to clinical follow-up, serial echocardiograms and chest X-ray films were obtained. RESULTS: The procedure was considered successful in 46 patients after a mean follow-up period of 3.6 +/- 3.3 months. Two patients required an early operation, one for bleeding from a pericardial vessel and one for persistent pericardial catheter drainage. Two patients required a late operation for recurrent tamponade. Minor complications of the procedure included fever in 6 of the first 37 patients (studied before the prophylactic use of antibiotic agents), thoracentesis or chest tube placement in 8 and a small spontaneously resolving pneumothorax in 2. Despite the short-term success of this procedure, the long-term prognosis of the 44 patients with malignant pericardial disease remained poor (mean survival time 3.3 +/- 3.1 months). CONCLUSIONS: Percutaneous balloon pericardiotomy is successful in helping to manage large pericardial effusions, particularly in patients with a malignant condition. It may become the preferred treatment to avoid a more invasive procedure for patients with pericardial effusion and a limited life expectancy.

Aged↗
PubMed1993

Inhibition of smooth muscle cell proliferation and experimental angioplasty restenosis by beta-cyclodextrin tetradecasulfate.

Heparin inhibits smooth muscle cell proliferation in vitro, a property that makes it potentially useful in preventing restenosis after angioplasty. Its utility in this setting is limited by the inability to use high doses (secondary to anticoagulant effects) and the need for subcutaneous administration. We tested the ability of beta-cyclodextrin tetradecasulfate (CDT), a nonanticoagulant synthetic heparin mimic, to inhibit smooth muscle cell proliferation in vitro and tested its efficacy when orally administered for the prevention of angioplasty restenosis in a rabbit atherosclerosis model. Vascular smooth muscle cells were cultured from rabbit aortas by the explant technique. Passaged cells were plated at low density in microtiter plates in the presence or absence of varying concentrations of heparin or CDT in culture medium containing 10% fetal calf serum. Using both 3H-thymidine incorporation and total protein assays, both heparin and CDT caused a similar dose-dependent inhibition of proliferation. We next tested the effect of orally administered CDT in the prevention of restenosis in focal femoral artery arteriosclerotic lesions created in hypercholesterolemic New Zealand White rabbits by air-dessication endothelial injury and subsequent peripheral angioplasty. Animals were followed up for 1 month and were fed normal chow supplemented by tap water with or without CDT. In animals receiving the highest concentration of CDT (2 mg/mL drinking water), the percentage of arterial cross-sectional area with intimal hyperplasia decreased from 50.5 +/- 1.7% (control) to 26.9 +/- 2.2% (p < 0.001), with the intimal/medial ratio being decreased from 1.4 +/- 0.4 to 0.5 +/- 0.2 (p = 0.056).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty↗
PubMed1992

Failure of endocardial biopsy from the internal jugular vein due to endocardial scar: a new indication for the femoral venous approach.

Following cardiac transplantation, patients undergo serial endomyocardial biopsies to evaluate rejection, usually by the internal jugular approach. A case report and data are presented that demonstrate that this approach becomes less efficient and occasionally impossible in the third year after transplant (53% success rate per biopsy attempt) as compared to the first year after transplant (80%) probably due to the development of endocardial scar in the area sampled by the bioptome. Alternatively, one can change to the femoral venous approach which continues to have a high success rate in the third year after transplant (83%) because a different area of the interventricular septum is sampled when this approach is used.

Biopsy↗
PubMed1992

Management and immediate outcome of patients with intracoronary thrombus during percutaneous transluminal coronary angioplasty.

A retrospective analysis of our experience with intraprocedural thrombus complicating percutaneous transluminal coronary angioplasty (PTCA) was undertaken. Of 983 PTCA procedures reviewed, 62 (6.3%) were complicated by thrombus. Patients were managed conservatively (group I, n = 18), with redilation (group II, n = 17), or with intracoronary urokinase and redilation (group III, n = 27). The three groups did not differ with respect to demographic or baseline angiographic variables, but complications, defined as death, myocardial infarction, bypass surgery, or threatened occlusion requiring emergency stenting, occurred in 11% of patients in group I, 24% in group II, and 48% in group III. Occlusive thrombus behavior was observed in 80% of these 62 patients. Patients with complications were less likely to have received antecedent antiplatelet therapy (79% vs 95% of patients without complications), had more complex baseline lesion morphology, more often had thrombus present at baseline (42% vs 19%), and more often had a low activated clotting time at the start of PTCA (53% vs 8%). Thrombi that led to complications more frequently exhibited occlusive behavior before therapy was begun (95% vs 71%) and more often occurred in the setting of intimal dissection (42% vs 14%). Patients undergoing PTCA at the time of diagnostic catheterization were more likely to have complications than those in whom PTCA was delayed. A successful outcome was more likely (83% vs 27%, p = 0.03) in group III if at least 140,000 U of urokinase were administered within 50 minutes of the appearance of thrombus. Thus intracoronary thrombus formation during PTCA remains a significant source of morbidity.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1992

Factors influencing immediate results, complications, and short-term follow-up status after Inoue balloon mitral valvotomy: a North American multicenter study.

Clinical trials with the Inoue mitral valvotomy balloon have recently begun in the United States. We assessed the effects of 17 demographic, echocardiographic, procedural, and hemodynamic variables on the immediate results, complications, and short-term follow-up of 200 patients in 15 centers undergoing valvotomy with this device. The study population had a mean age +/- SD of 53 +/- 15 years, and the total echocardiographic score was 7.2 +/- 2.4. Valvotomy was technically successful in 96.5% of procedures and increased the mean mitral valve area from 1.0 +/- 0.3 to 1.8 +/- 0.7 cm2 (p less than 0.001); 72% had an increase in valve area greater than or equal to 50%, and 67% had a final area greater than or equal to 1.5 cm2. Major procedural complications included cardiac tamponade during transseptal puncture (1.0%), systemic embolism (1.5%), and severe mitral regurgitation (2.4%); there were no procedural deaths and one hospital death. Multivariate analysis identified the absence of prior surgical commissurotomy and younger age as significant predictors of the gain in mitral valve area, but the correlation coefficients were low. Although the absence of subvalvular disease on echocardiograms was a predictor of a final valve area greater than or equal to 1.5 cm2, the total echocardiographic score did not correlate well with the immediate outcome (r = 0.01, p = NS). No variable was identified as predictive of restenosis, which occurred according to echocardiographic criteria in 14 of 66 (21%) patients evaluated 6 months after valvotomy. Good hemodynamic results with valvotomy were achieved in the majority of patients with low complication rates by many investigators with the use of the Inoue balloon device.(ABSTRACT TRUNCATED AT 250 WORDS)

Balloon Occlusion↗
PubMed1992

Effects of atrial natriuretic peptide on myocardial contractile and diastolic function in patients with heart failure.

Atrial natriuretic peptide alters left ventricular performance in patients with heart failure. To assess the direct effects of this hormone on myocardial function, its actions were compared with those of the pure vasodilator nitroprusside in 10 patients with heart failure. Simultaneous left ventricular micromanometer pressure and radionuclide volume were obtained during a baseline period, during nitroprusside infusion, during a second baseline period and during atrial natriuretic peptide infusion. The baseline end-systolic pressure-volume relation was generated in nine patients from pressure-volume loops obtained during the two baseline periods and during afterload reduction with nitroprusside. Mean arterial pressure decreased with atrial natriuretic peptide (89 +/- 3 to 80 +/- 2 mm Hg, p less than 0.05) and by a greater amount with nitroprusside (90 +/- 4 to 73 +/- 3 mm Hg, p less than 0.05). Left ventricular end-diastolic pressure also decreased with atrial natriuretic peptide (24 +/- 2 to 16 +/- 3 mm Hg, p less than 0.05) and by a greater amount with nitroprusside (24 +/- 2 to 13 +/- 3 mm Hg, p less than 0.05). Cardiac index increased during infusion of each agent from 2.0 +/- 0.2 to 2.4 +/- 0.2 liters/min per m2 (p less than 0.01). Heart rate increased slightly with nitroprusside but did not change with atrial natriuretic peptide. Peak positive first derivative of left ventricular pressure (dP/dt), ejection fraction and stroke work index were unchanged by either agent. The relation between end-systolic pressure and volume during atrial natriuretic peptide infusion was shifted slightly leftward from the baseline value in four patients, slightly rightward in four and not at all in one patient, indicating no consistent inotropic effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Effect of valve deformity on results and mitral regurgitation after Inoue balloon commissurotomy.

BACKGROUND: The effect of valve deformity and patient age adversely affect the results of percutaneous transvenous mitral commissurotomy (PTMC) with conventional balloons. METHODS AND RESULTS: These factors were characterized after PTMC with the Inoue balloon. The increases in mitral valve area and mitral regurgitation after the procedure were evaluated comparing echocardiographic score of 8 or less versus more than 8, age of less than 60 versus age of 60 years or more, and age of less than 70 versus age of 70 years or more. One hundred sixty-two patients (mean age, 52 +/- 14 years) were studied. For the entire group, mitral valve area increased from 1.0 to 1.8 cm2 (p less than 0.001). Valve area increased from 1.0 +/- 0.3 to 1.8 +/- 0.6 cm2 in patients with echocardiographic score of 8 or less (n = 102) and from 1.0 +/- 0.3 to 1.7 +/- 0.5 cm2 with echocardiographic score of more than 8 (n = 44). Patients less than 60 years old (n = 104) had increases in valve area from 1.0 +/- 0.3 to 1.8 +/- 0.6 cm2 versus 1.0 +/- 0.4 to 1.8 +/- 0.6 cm2 for those 60 years old or older (n = 50) (p = NS). There was no significant difference in resultant valve area when the age division was increased to less than 70 versus 70 years or more. Similarly, the percentage of patients with 2+ or greater increase in mitral regurgitation was not different for those with higher than for those with lower echocardiographic scores (4% versus 12%, p = NS), age of less than 60 versus age of 60 years or more (10% versus 10%, p = NS), or age of less than 70 versus age of 70 or more years (9% versus 18%, p = NS). Valve replacement for mitral regurgitation was performed in four patients (one emergency), all with echocardiographic scores of less than 8. CONCLUSIONS: Age and extent of valve deformity do not have significant effects on acute results of PTMC using the Inoue balloon. Unique balloon geometry or the controlled, stepwise balloon sizing may explain these acceptable acute results in patients with more-deformed valves.

Adult↗
PubMed1992

Emergent use of balloon-expandable coronary artery stenting for failed percutaneous transluminal coronary angioplasty.

BACKGROUND: The balloon-expandable intracoronary stent developed by Palmaz and Schatz is undergoing clinical evaluation for use in unfavorable anatomic situations and in the prevention of restenosis. Because the stent's mechanism of action would suggest effectiveness in salvaging certain percutaneous transluminal coronary angioplasty (PTCA) failures, we retrospectively examined the results of emergency unplanned coronary artery stenting for failed PTCA procedures, including acute occlusion. METHODS AND RESULTS: The study population consisted of all US patients receiving emergency unplanned stent implantation in a nonrandomized fashion at seven centers over a 2 1/2-year period (n = 56). All available medical records and angiograms were reviewed to determine retrospectively the reason for stenting: Group 1 consisted of 23 patients with a suboptimal angioplasty result; group 2 included patients with evidence of impending vessel closure after PTCA (n = 15); and group 3 were patients with frank acute occlusion after PTCA (n = 18). The immediate and final (30-day) results of stenting were examined with respect to major complications, which included death, need for coronary artery bypass graft surgery, and occurrence of myocardial infarction. Finally, restenosis rates (greater than or equal to 50% stenosis) based on follow-up angiography were calculated. Baseline characteristics of the study population included a mean +/- SD age of 58 +/- 11 years and a large prevalence of angiographic characteristics generally considered unfavorable for PTCA, which include lesion eccentricity (49%), intimal dissection (9%), or angiographically visible thrombus (6%). After conventional balloon angioplasty, there was an increased incidence of intimal dissection (74%) and thrombus formation (38%), and overall stenosis severity was unchanged (75 +/- 12% versus 70 +/- 27%, p = NS). Successful stent deployment was achieved in 55 (98%) of 56 patients with initial success (freedom from death, surgery, and infarction) in 52 (93%) of 56 patients. The success rate at 1 month fell to 71% primarily because of the occurrence of subacute stent thrombosis (16%) and its associated complications. Overall, major complications occurred in 16 (29%) of 56 patients within 30 days. The only predictor of subacute stent thrombosis in multiple stepwise logistic regression analysis was the presence of angiographically visible thrombus after stenting (p = 0.03). Angiographic restenosis was documented in eight (23%) of 35 eligible patients. CONCLUSIONS: Emergency stenting may be a useful and effective treatment for failed angioplasty. High initial success rates (greater than 90%) can be achieved, but subsequent complications, often related to subacute thrombosis, occur in a substantial portion of patients. Patients who receive stents on an emergency basis, particularly those with previous acute occlusion, should be considered to be at greater than usual risk for complications and receive more careful anticoagulation and follow-up.

Aged↗
PubMed1992

Effects of pacing tachycardia and balloon valvuloplasty on pulmonary artery impedance and hydraulic power in mitral stenosis.

BACKGROUND: Mitral stenosis is characterized by progressive pulmonary hypertension and eventual right ventricular failure. However, the correlation between right ventricular failure and the level of pulmonary hypertension is poor, suggesting that factors other than those recognized from nonpulsatile hemodynamic parameters may contribute to impaired right ventricular performance in this condition. METHODS AND RESULTS: We studied 16 patients with severe mitral stenosis (mean valve area, 1.0 +/- 0.2 cm2) at supine rest and during pacing tachycardia using high-fidelity catheter recordings of pulmonary artery (PA) pressure and flow velocity. Pulmonary impedance spectra, wave reflection properties, and hydraulic power data were derived from Fourier analysis of signal-averaged data. Pacing tachycardia (baseline heart rate, 81 +/- 11 beats per minute; pacing, 132 +/- 11 beats per minute) significantly raised pulmonary wedge and mean PA pressures. There was no change in pulmonary vascular resistance (209 +/- 144 to 232 +/- 164 dyne-sec/cm5) or PA characteristic impedance (62 +/- 25 to 55 +/- 28 dyne-sec/cm5). However, first harmonic impedance (Z1) significantly decreased (134 +/- 71 to 100 +/- 68 dyne-sec/cm5; p < 0.001). Accordingly, oscillatory and total dissipated hydraulic power per unit forward flow (WT/CO) fell during tachycardia (2.6 +/- 1.6 to 2.3 +/- 1.4 mW/ml.sec-1; p = 0.06) despite acute pulmonary hypertension. Reflected pressure waves returned earlier to the proximal PA, suggesting increased vessel stiffness. Immediately after percutaneous balloon mitral valvuloplasty (PBV) in eight of the patients, baseline and pacing data were again recorded. Compared with the pre-PBV baseline state, post-PBV resting data demonstrated no change in resistance or characteristic impedance, but there was a significant fall in Z1 (166 +/- 75 to 103 +/- 45 dyne-sec/cm5; p < 0.05) and in the magnitude of pulmonary wave reflections. WT/CO tended to decrease after PBV, and pacing after PBV produced a further decrease in WT/CO, again in association with lower Z1. CONCLUSIONS: These data demonstrate that 1) increased pulmonary characteristic impedance, although a feature of mitral stenosis, is not exacerbated by the acute effects of increased distending pressure; 2) pacing tachycardia in mitral stenosis causes little change in the pulmonary impedance spectrum except at low frequencies, where decreased impedance lowers power requirements per unit flow; and 3) relief of mitral stenosis produces immediate improvement in low-frequency impedance and in hydraulic power requirements. These findings suggest that although characteristic impedance may be a measure of the long-term effects of pulmonary hypertension on the pulmonary circulation, acute increases and decreases in PA pressure produce effects on right ventricular load that are best described in terms of the low-frequency properties of the PA system. Improvement in low-frequency impedance diminishes hydraulic power requirements and thus reflects improved ventricular-vascular coupling, irrespective of distending PA pressure. Efforts to treat or prevent right heart failure in the presence of pulmonary hypertension should take account of the potential benefit of changes in low-frequency impedance characteristics of the pulmonary vascular bed.

Adult↗