Biomedical subjects

V Mathew

Publications and source records attributed to V Mathew.

At least 37 records · Page 2Linked to original sources

PubMed2000

Immediate and late outcomes after direct stent implantation without balloon predilation.

OBJECTIVES: The aim of our study was to compare the in-hospital and long-term clinical outcomes of direct coronary stenting with balloon predilation followed by stent placement. BACKGROUND: With improvement in stent designs, the practice of direct stenting without balloon predilation has become more widespread. METHODS: We analyzed the Mayo Clinic Coronary Intervention data base between January 1, 1995 and March 5, 1999 and identified 777 patients who were treated with direct stenting (DS) and 3,176 patients treated with balloon angioplasty plus stenting (BA+S). RESULTS: The procedural success rates between the DS and BA+S groups were not significantly different (96.3% vs. 96.4%). The ability to deliver the stent in a subgroup of patients who had DS was 95%, with 5% requiring crossover to predilation. Multivariate analysis showed no significant differences with respect to in-hospital death (odds ratio [OR] 0.9, 95% confidence interval [CI] 0.5 to 1.8), in-hospital myocardial infarction (OR 0.9, 95% CI 0.6 to 1.2) or revascularization (OR 0.7, 95% CI 0.4 to 1.5) in the DS compared with the BA+S group. Long-term outcomes were not significantly different between the DS and BA+S groups. The procedural duration was significantly shorter in the DS group, and there was a decreased utilization of contrast agent, balloons and wires. CONCLUSIONS: The in-hospital and long-term clinical outcomes in patients undergoing a coronary intervention are equivalent when comparing stenting without balloon predilation with balloon angioplasty followed by stenting. Direct stenting is associated with decreased utilization of contrast agent and equipment and shorter procedure times. A randomized study should be performed to better determine the impact of this technique on short- and long-term procedural outcomes.

Aged↗

PubMed2000

Effect of age on the outcome of angioplasty for acute myocardial infarction among patients treated at the Mayo Clinic.

PURPOSE: Elderly patients, especially those 80 years of age and older, have been excluded from most studies of thrombolysis or primary coronary angioplasty in patients with acute myocardial infarction. We compared the outcomes of elderly patients who underwent coronary angioplasty with the outcomes of younger patients and determined whether there were any temporal trends in survival. PATIENTS AND METHODS: We reviewed the outcomes of 1,597 consecutive patients who underwent primary coronary angioplasty between 1979 and 1997, including 127 patients who were 80 years of age or older (mean [+/-SD] age, 83 +/- 3 years, 47% male). Their in-hospital and long-term outcomes were compared with those of 524 patients who were 70 to 79 years old, 527 patients who were 60 to 69 years old, and 419 patients who were 50 to 59 years old. The oldest group of patients was divided into two groups, based on whether they had intervention through the end of 1993 (n = 56) or between 1994 and 1997 (n = 71). The survival rate of the patients who had no complications and left the hospital was compared with expected survival based on age- and sex-adjusted data. RESULTS: Patients 80 years of age or older had more adverse baseline characteristics, including risk factors and comorbid conditions, than the younger patients. The clinical success rate of primary angioplasty in this group was lower than those in the other three groups (61% versus 74% in those aged 70 to 79 years, 73% in those aged 60 to 69 years, and 81% in those aged 50 to 59 years, P < 0.001). The in-hospital mortality rate among patients 80 years of age or older was significantly greater than among patients in the other three groups (21% in those aged 80 years or older, 13% in those aged 70 to 79 years, 9% in those aged 60 to 69 years, and 4% in those aged 50 to 59 years, P < 0.001 ). The clinical success rate of the angioplasty improved significantly in the more recent period (75% versus 45%, P = 0.0006) and in-hospital mortality declined (16% versus 29%, P = 0.07). During follow-up, mortality in the oldest age group in whom angioplasty was successful was significantly greater than in the three younger groups, but was similar to the expected survival in the general US population. CONCLUSIONS: The mortality associated with primary angioplasty for acute myocardial infarction in octogenarians remains high, although there has been significant improvement in the clinical success rate. The long-term prognosis following a successful angioplasty is not different from that in an age- and sex-adjusted U.S. white population.

Age Factors↗

PubMed2000

Percutaneous coronary interventions in patients with prior coronary artery bypass surgery: changes in patient characteristics and outcome during two decades.

PURPOSE: Patients who develop recurrent myocardial ischemia after coronary artery bypass graft (CABG) surgery are often referred for percutaneous coronary interventions. The objective of this study was to evaluate the changing demographic and clinical characteristics, and procedural and long-term outcomes, in patients with prior CABG referred for percutaneous coronary interventions during a 20-year period. METHODS: We prospectively collected data on patients who underwent coronary interventional procedures following CABG surgery. We compared angiographic and procedural success, and long-term event-free survival, among patients who had procedures from 1979 to 1989 (n = 393), from 1990 to 1994 (n = 811), and from 1995 to 1998 (n = 937). RESULTS: Patients in the 1995 to 1998 cohort were older, had a lower mean left ventricular ejection fraction, and were more likely to have diabetes, hypertension, and hyperlipidemia, but less likely to smoke. They were more likely to have treatment of complex lesions, including vein graft lesions, and had more prior CABG surgeries. More patients received intracoronary stents in 1995 to 1998. Both angiographic success rates (78% from 1979 to 1989, 88% from 1990 to 1994, and 91% from 1995 to 1998, P < 0.0001) and procedural success rates (78%, 86%, and 91%, P < 0.0001) improved with time. Long-term mortality was greater in the pre-1990 group (relative risk = 1.8, 95% confidence interval: 1.3 to 2.4) and 1990 to 1994 group (relative risk = 1.7, 95% confidence interval: 1.3 to 2.2) compared with the 1995 to 1998 group, as were the likelihoods of repeat revascularization and recurrent severe angina. CONCLUSION: Although the demographic and clinical characteristics of patients who underwent percutaneous intervention following CABG surgery indicate that they are at increasingly greater risk of adverse cardiac events, success rates and long-term survival have improved with time. The rates of recurrent severe angina as well as of subsequent revascularization have also decreased, probably as a result of improvements in technique and greater use of stents and adjunctive medications.

Aged↗

PubMed2000

Increased coronary effects of stimulation of endothelin-B receptor in experimental hypercholesterolemia.

BACKGROUND: Vasoconstriction in response to endothelin-1 has been shown to be primarily related to its effects on the endothelin-A receptor. Experimental hypercholesterolemia is associated with an increase in coronary vasoconstrictor response to endothelin-1 in vivo, although the relative contributions of subtypes of endothelin receptor in this model remain unknown. OBJECTIVE: To test the hypothesis that there is an increase in coronary vasoconstriction in response to stimulation of endothelin-B receptor in hypercholesterolemia, which might be related to attenuation of activity of endothelin-derived relaxing factor. METHODS: We infused 5 ng/kg/min sarafotoxin, a specific endothelin-B receptor agonist, or 50 micrograms/kg/min NG-monomethyl-L-arginine (L-NMMA), a competitive inhibitor of nitric oxide synthase, into the left anterior descending coronary arteries of pigs before and after feeding them a cholesterol-rich diet for 10 weeks. RESULTS: There was a significant increase in serum level of cholesterol. After 10 weeks, infusion of sarafotoxin resulted in an accentuated decrease in coronary blood flow (CBF) compared with baseline (decreases by 60 +/- 7 versus 34 +/- 6%, P < 0.05). There was no significant difference between the effects on diameter of coronary arteries for the two time periods. The effect of L-NMMA on CBF was attenuated after 10 weeks (by 5 +/- 10.1 versus 45.6 +/- 4.7%, P < 0.05). Endothelin-receptor status of epicardial coronary arteries remained unchanged. Sarafotoxin and L-NMMA were co-infused at the above-mentioned doses into normolipidemic animals; the decrease in CBF in response to this co-infusion was comparable to the decrease observed with sarafotoxin alone in hypercholesterolemic animals (decreases of 67 +/- 5 versus 60 +/- 7, NS). CONCLUSIONS: The present results demonstrate that selective stimulation of the endothelin-B receptor increases coronary vasoconstriction in experimental hypercholesterolemia, primarily at the level of the microvasculature. These findings may be related to the attenuation of activity of endothelin-derived relaxing factor in this model, and support the hypothesis that endothelin-B receptor plays a role in the regulation of coronary vascular tone in pathophysiologic states.

Animals↗

PubMed1999

Baseline clinical and angiographic variables associated with long-term outcome after successful intracoronary stent implantation.

Although randomized studies have demonstrated improved outcomes with stents over balloon angioplasty in straightforward coronary narrowings in low-risk patients, this advantage is less clear for complex lesions and high-risk patients. This study was designed to identify clinical and angiographic variables that are associated with long-term outcome after stent implantation. We identified 1,709 patients undergoing successful stent placement without in-hospital major adverse events. We analyzed clinical, lesional, and procedural variables to determine their correlation with outcome. Mean duration of follow-up was 1.6 +/- 1.4 years. Cox proportional-hazards models and stepwise methods were used to assess which covariates were potentially related to each end point. The occurrence of death/myocardial infarction (MI) was associated with any history of congestive heart failure (relative risk [RR] 3.3, 95% confidence interval [CI] 2.3 to 4.7, p <0.0001), procedure within 24 hours of MI (RR 2.3, CI 1.3 to 4.1, p = 0.0048), vein graft intervention (RR 1.8, CI 1.3 to 2.6, p = 0.0007), and prior MI (RR 1.8, CI 1.2 to 2.6, p = 0.004). Repeat revascularization was associated with multivessel stent placement (RR 1.8, CI 1.2 to 2.8, p = 0.006) and stent for abrupt closure (RR 1.7, CF 1.1 to 2.7, p = 0.03), but was less frequent with de novo lesions and right coronary artery lesions (RR 0.6, CI 0.5 to 0.8, p = 0.0007, and RR 0.8, CI 0.6 to 1.0, p = 0.05, respectively). The cumulative end point of death/MI/repeat revascularization was associated with congestive heart failure (RR 1.7, CI 1.3 to 2.2, p <0.0001), multivessel stent placement (RR 1.6, Cl 1.1 to 2.3, p = 0.03), warfarin therapy (RR 1.4, CI 1.2 to 1.8, p = 0.001), and procedure within 24 hours of MI (RR 1.5, CI 1.1 to 2.1, p = 0.02), but was less frequent with complete revascularization and right coronary artery intervention (RR 0.8, CI 0.7 to 0.99, p = 0.04, and RR 0.7, CI 0.6 to 0.9, p = 0.009, respectively). Thus, this study demonstrates that there are readily identifiable characteristics in patients treated successfully with stents that are associated with long-term outcome.

Anticoagulants↗

PubMed1999

Clinical outcome after multivessel coronary stent implantation.

BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) has been shown to be an effective therapy for multivessel coronary artery disease, although more frequent acute complications and an increased need to repeat revascularization than with single-vessel PTCA continue to be limitations. Intracoronary stent placement has been shown to reduce the rate of acute complications and the need for subsequent revascularization. We sought to evaluate the outcome among patients undergoing successful multivessel coronary intervention with stents. METHODS: The participants were 175 patients without coronary artery bypass grafts who underwent multivessel coronary revascularization in which stent placement was attempted in all treated segments from January 1992 through March 1998 at our institution. Clinical and angiographic characteristics and outcomes were analyzed. RESULTS: Stent placement was attempted for 428 coronary lesions. The angiographic success rate was 100%. Modified American College of Cardiology-American Heart Association type B2 and C lesions accounted for 74.5% of the lesions. Three patients (1.7%) died in the hospital. No patient had Q-wave myocardial infarction or needed coronary artery bypass grafting. Procedural success was achieved for 172 patients (98.3%). The Kaplan-Meier probability of freedom from death or myocardial infarction at 12 months was 96.6%, of any revascularization was 81. 7%, and of death, myocardial infarction, and any revascularization combined was 79.8%. The use of long-acting nitrates at 12 months was reduced (34.3% versus 19.1%, P =.01). CONCLUSIONS: Multivessel coronary stent placement is associated with an excellent procedural success rate despite a high rate of adverse lesion characteristics and a high event-free survival rate during the follow-up period. The likelihood that revascularization will not have to be repeated during the first follow-up year is significantly better than that for historic controls of multivessel PTCA.

Aged↗

PubMed1999

The influence of abciximab use on clinical outcome after aortocoronary vein graft interventions.

OBJECTIVES: The purpose of this study was to evaluate the effect of abciximab use on clinical outcome in aortocoronary vein graft interventions. BACKGROUND: Although large randomized trials have demonstrated a significant benefit of abciximab use in the setting of percutaneous coronary interventions, there is relatively little data with respect to the use of this agent in percutaneous vein graft interventions. METHODS: Three hundred and forty-three patients were identified; 210 undergoing vein graft intervention without abciximab and 133 patients with abciximab. RESULTS: There were differences in baseline clinical and angiographic characteristics between the two groups; advanced age, unstable angina, older vein grafts and thrombus containing lesions were relatively common in both groups. Angiographic and procedural success rates were similar with or without the use of abciximab (89% vs. 92%, p = 0.15, and 85% vs. 91%, p = 0.12, respectively). The in-hospital composite end point of death/Q-wave myocardial infarction (QWMI)/repeat revascularization was similar between the two groups. Utilizing statistical modeling to adjust for baseline differences between the groups, abciximab use did not influence the cumulative long-term composite end point of death/MI/repeat revascularization. CONCLUSIONS: This study demonstrates that in this relatively high-risk population undergoing aortocoronary vein graft interventions, the administration of abciximab periprocedurally does not appear to reduce major adverse clinical events.

Abciximab↗

PubMed1999

Clopidogrel versus ticlopidine after intracoronary stent placement.

OBJECTIVES: The study compared the safety and efficacy of ticlopidine with clopidogrel in patients receiving coronary stents. BACKGROUND: Stent thrombosis is reduced when ticlopidine is administered with aspirin. Clopidogrel is similar to ticlopidine in chemical structure and function but has fewer side effects; few data are available about its use in stent patients. METHODS: We compared 30-day event rates in 500 consecutive coronary stent patients treated with aspirin and clopidogrel (300 mg loading dose immediately prior to stent placement, and 75 mg/day for 14 days) to 827 consecutive stent patients treated with aspirin and ticlopidine (500 mg loading dose and 250 mg twice daily for 14 days). RESULTS: Patients treated with clopidogrel had more adverse clinical characteristics including older age, more severe angina, and more frequent infarction within the prior 24 h. Nonetheless, mortality was 0.4% in clopidogrel patients versus 1.1% in ticlopidine patients; nonfatal myocardial infarction occurred in 0% versus 0.5%, stent thrombosis in 0.2% versus 0.7%, bypass surgery or repeat angioplasty in 0.4% versus 0.5%, and any event occurred in 0.8% versus 1.6% of patients, respectively (p = NS). Based on the observed 30-day event rate of 1.6% with ticlopidine, the statistical power of the study was 43% to detect an even rate of 0.5% with clopidogrel, and 75% to detect an event rate with of 4% with clopidogrel, with a p value of 0.05. CONCLUSIONS: These data indicate that clopidogrel can be safely substituted for ticlopidine in patients receiving coronary stents.

Aged↗

PubMed1998

Clinical outcome of patients undergoing multivessel coronary stent implantation.

OBJECTIVES: To evaluate the outcome of patients undergoing multivessel coronary stent implantation. BACKGROUND: Percutaneous transluminal coronary angioplasty has been shown to be an effective treatment for multivessel coronary artery disease, although the need for repeat revascularization continues to be a limitation. Intracoronary stent placement has been shown to reduce the need for subsequent revascularization. METHODS: Seventy-seven patients without prior coronary artery bypass grafting (CABG) undergoing multivessel coronary revascularization in which stents were placed in all treated segments over a 5 year period at our institution were identified. Clinical and angiographic characteristics and outcomes were analyzed. RESULTS: One hundred and eighty-eight coronary lesions were successfully treated (2.1+/-0.3 treated vessels/patient, 2.4+/-0.6 treated lesions/patient) using 2.8+/-1.2 stents/patient (range 2-9) and 1.4+/-0.8 stents/vessel (range 1-6). Procedural success rate [angiographic success without in-hospital death, Q-wave myocardial infarction (Q-wave MI) or CABG] was achieved in 76 of 77 patients (98.7%). Anatomically complete revascularization was achieved in 46 (59.7%) patients. Modified ACC/AHA Type B2 and C lesions comprised 75.5% of the 188 lesions. The left anterior descending artery was treated in 57 (74.0%) patients. The indication for stent placement was dissection or threatened/abrupt closure in 54 segments (28.8%). In-hospital events included death in one patient (1.3%); no patient suffered a Q-wave MI or required CABG. Stent occlusion occurred in two (2.6%) patients, and repeat percutaneous intervention of the target vessel was also required in these two patients. Any of these adverse events occurred in three (3.9%) patients. No further events occurred after hospital discharge in the 30 days after the procedure. Of hospital survivors (n=76), adverse events at 6 months included death in two patients (2.6%), MI in two (2.6%), CABG in six (7.9%); nine (11.8%) patients underwent repeat percutaneous intervention and 15 (19.7%) underwent any revascularization. CONCLUSIONS: Multivessel coronary stent placement is associated with an excellent procedural success rate despite a high rate of adverse lesion characteristics, and a low rate of death or MI during follow-up. The need for further revascularization compares favorably with published rates with multivessel PTCA and single stent implantation for discrete de novo lesions.

Aged↗

PubMed1998

New insight into coronary endothelial dysfunction: role of endothelin.

The coronary endothelium plays a central role in the modulation of coronary vascular tone via the production and release of vasoactive mediators. A number of cardiovascular disease states are associated with coronary endothelial dysfunction, which results in an imbalance between vasoactive substances. Endothelin is a potent vasoconstrictor produced by the coronary endothelium and has been implicated in the pathogenesis of coronary endothelial dysfunction. This review examines the relationship between endothelin and coronary endothelial dysfunction as it occurs in a number of cardiovascular disease states and explores potential therapeutic options.

Animals↗

PubMed1998

Management of tuberculosis in Wales: 1986-92.

OBJECTIVES: To describe the epidemiology of childhood tuberculosis in Wales and to assess the standard of management of patients with tuberculosis. DESIGN: Retrospective study of data retrieved from case notes and review of radiographs of all identified patients. SUBJECTS: Forty eight cases of tuberculosis and 10 of tuberculosis chemoprophylaxis in children under 15 years of age, in Wales, between January 1986 and December 1992. MAIN OUTCOME MEASURES: Management of childhood tuberculosis in Wales compared with the published recommendations of the Joint Tuberculosis Committee of the British Thoracic Society. RESULTS: Documentation was poor in most of the 48 cases of tuberculosis and only 31 (65%) were formally notified. One third of patients were asymptomatic and were detected by contact tracing; only eight (17%) were culture positive. Only 20% of patients from ethnic minorities had previously been immunised with BCG. Management and chemotherapy varied widely. Few patients were managed jointly by paediatricians and chest doctors. Only 10% completed treatment with a recommended chemotherapy regimen. In 37% of patients treatment was inadequate, and in the remainder either the choice of drugs or the duration of treatment was inappropriate. No patient died, nor had any relapsed by June 1995. CONCLUSIONS: Very few cases of childhood tuberculosis were managed according to the recommendations of the British Thoracic Society.

Adolescent↗

PubMed1998

Acute endothelin-receptor inhibition does not attenuate acetylcholine-induced coronary vasoconstriction in experimental hypercholesterolemia.

Endothelin (ET) may mediate the enhanced coronary vasoconstriction associated with hypercholesterolemia. We hypothesized that short-term inhibition of ET receptors attenuates the coronary epicardial vasoconstrictor response to acetylcholine in experimental hypercholesterolemia. ET-1 (group I, n=5; 5 ng x kg[-1] x min[-1]) and acetylcholine (group III, n=7; 10[-6] to 10[-4] mol/L) were given by intracoronary infusion in pigs. ET-1 and acetylcholine were also infused with the specific ETA-receptor blocker FR-139317 (5 microg x kg[-1] x min[-1]; group II, n=6; group IV, n=6). Acetylcholine was also infused with the combined ET-receptor blocker, bosentan (0.5 mg/kg plus 1 mg x kg[-1] x h[-1], group V, n=5). The ETB-receptor agonist sarafotoxin 6c (5 ng x kg[-1] x min[-1]; n=4) was also infused. The percentage change in coronary artery diameter (%deltaCAD) to the infusions was measured at baseline and after 10 weeks of high-cholesterol diet in all animals. Sarafotoxin 6c mildly reduced %deltaCAD at baseline and 10 weeks (-10+/-2% and -12+/-3%, respectively). FR-139317 did not attenuate the epicardial vasoconstrictor response to ET-1 at baseline (%deltaCAD -18+/-8% for group I versus -12+/-6% for group II; P=NS) but did at 10 weeks (%deltaCAD -77+/-14% for group I versus -14+/-6% for group II; P<.05). FR-139317 did not affect the response to acetylcholine at baseline (%deltaCAD 5+/-2% for group III versus 7+/-3% for group IV, P=NS) or at 10 weeks (%deltaCAD -23+/-12% for group III versus -19+/-7% for group IV; P=NS). Bosentan did not affect the response to acetylcholine at baseline or 10 weeks. Short-term ET-receptor inhibition in experimental hypercholesterolemia attenuated the enhanced coronary epicardial vasoconstrictor effects of ET-1 but not acetylcholine-induced coronary epicardial vasoconstriction, suggesting that acetylcholine-induced coronary epicardial vasoconstriction may not be mediated by ET receptors.

Acetylcholine↗

PubMed1998

Predictors of smoking cessation after percutaneous coronary revascularization.

OBJECTIVE: To identify factors predictive of smoking cessation after successful percutaneous coronary revascularization. MATERIAL AND METHODS: We undertook a case-control study of the smoking status of all patients at Mayo Clinic Rochester from September 1979 through December 1995 who were smokers at the time of an index percutaneous coronary revascularization procedure in the non-peri-infarction setting (no myocardial infarction within 24 hours). Maximal duration of prospective follow-up was 16 years. Patients were classified into those who permanently quit smoking immediately after the procedure (N = 435; mean follow-up, 5.1 +/- 3.7 years) or those who continued to smoke at some time during follow-up (N = 734; mean follow-up, 5.3 +/- 3.7 years). Logistics regression models were formulated to determine independent predictors of smoking cessation. RESULTS: Predictors of continued smoking were greater prior cigarette consumption (odds ratio [OR] = 1.009 for each pack-year; 95% confidence interval [CI] = 1.004 to 1.014) and having one or more risk factors for coronary artery disease other than cigarette smoking (OR = 1.49; 95% CI = 1.15 to 1.93). Older age (OR = 0.98 for each additional year; 95% CI = 0.97 to 0.99) and unstable angina at time of initial assessment (OR = 0.69; 95% CI = 0.52 to 0.91) were associated with less likelihood of continued smoking. CONCLUSION: Younger patients with a worse risk profile and greater prior cigarette consumption were more likely than other patients to continue smoking after percutaneous coronary revascularization in the non-peri-infarction setting. Patients who had unstable angina were more likely to quit smoking than those who had stable angina. Despite the proven benefits of smoking cessation after percutaneous coronary revascularization, a substantial proportion of smokers (63%) continue to smoke; thus, smoking-cessation counseling should be addressed in this population.

Aged↗

PubMed1997

Symptomatic conduction system disease in cardiac amyloidosis.

Symptomatic conduction system disease in cardiac amyloidosis and its management has been reported infrequently. We report our experience of patients with amyloidosis having symptomatic conduction system disease requiring permanent pacemaker implantation.

Aged↗

PubMed1997

Enhanced endothelin-mediated coronary vasoconstriction and attenuated basal nitric oxide activity in experimental hypercholesterolemia.

BACKGROUND: Experimental hypercholesterolemia is associated with coronary vasomotor dysfunction. This study was designed to test the hypothesis that experimental hypercholesterolemia is characterized by altered coronary vasomotor responses to endothelin and inhibition of the endogenous NO pathway. METHODS AND RESULTS: Endothelin-1 (ET-1) at 5 ng x kg(-1) x min(-1) or N(G)-monomethyl-L-arginine (L-NMMA), a competitive inhibitor of nitric oxide synthase (NOS), at 50 microg x kg(-1) x min(-1) was infused into the left anterior descending coronary artery in pigs before and after 10 weeks of cholesterol diet. There was a significant increase in serum cholesterol. At 10 weeks, ET-1 resulted in an accentuated decrease in coronary blood flow (CBF) and coronary artery diameter (CAD) compared with baseline (-88+/-6% versus -45+/-9%, P<.05, and -77+/-14% versus -18+/-8%, P<.05, respectively) and an increase in coronary vascular resistance (CVR) (242+/-18% versus 110+/-17%, P<.05); ET receptor density and binding affinity in epicardial coronary arteries were unchanged. The effect of L-NMMA on CBF, CAD, and CVR was attenuated at 10 weeks (-7+/-8% versus -48+/-4%, -2+/-3% versus -17+/-5%, and 16+/-10% versus 125+/-32%; each P<.05). Immunohistochemistry staining for constitutive NOS revealed a decrease in immunoreactivity in the coronary arteries of hypercholesterolemic pigs. CONCLUSIONS: The present study demonstrates an enhanced coronary vasoconstrictive response to pathophysiological doses of endothelin and an attenuated response to the inhibition of endogenous NO activity, suggesting an alteration in coronary vascular reactivity in experimental hypercholesterolemia.

Acetylcholine↗

PubMed1997

Atrioventricular sequential pacing in cardiac amyloidosis: an acute Doppler echocardiographic and catheterization hemodynamic study.

BACKGROUND AND HYPOTHESIS: Congestive heart failure due to cardiac amyloidosis is often refractory to conventional medical management and is associated with a high mortality rate. Recently, dual-chamber pacemaker implantation has been proposed as a therapeutic option in the management of patients with certain forms of cardiomyopathy with persistent heart failure symptoms, despite optimal medical therapy. The present study evaluates the acute hemodynamic response to atrioventricular (AV) pacing in patients with cardiac amyloidosis who presented with refractory heart failure symptoms. METHODS: Three patients with medically refractory heart failure due to cardiac involvement of amyloidosis underwent a simultaneous cardiac catheterization/Doppler echocardiography study with acute AV sequential pacing at varying AV intervals. RESULTS: During pacing at various AV intervals, all patients showed an increased in their filling pressures and either no change or decline in their cardiac index. CONCLUSION: The current study demonstrates an absence of acute hemodynamic with AV sequential pacing in patients with amyloid heart disease and medically refractory heart failure symptoms.

Aged↗

PubMed1997

Clinical outcome of patients undergoing endoluminal coronary artery reconstruction with three or more stents.

OBJECTIVES: We sought to evaluate the outcome of patients undergoing multiple (three or more), contiguous stent implantation within a single native coronary artery. BACKGROUND: The implantation of multiple stents within a single coronary artery is increasing in frequency, although the outcome of such patients is not well described. METHODS: Forty-five patients without previous coronary artery bypass graft surgery (CABG) undergoing multiple, contiguous stent implantation in a single coronary artery were identified. Clinical and angiographic characteristics and outcomes were analyzed. RESULTS: The angiographic success rate was 97.8%. The procedural success rate was 91.1%; stent occlusion during the initial hospital period occurred in four patients (8.9%). Death, myocardial infarction (MI), CABG, repeat target vessel intervention or severe angina occurred in 10 (23.3%) of 43 hospital survivors at 6-months follow-up. The indication for stent placement was threatened or abrupt closure in 30 patients (66.7%). Of the 25 patients with abrupt or threatened closure whose clinical and angiographic data would have indicated emergent CABG had stents not been available, the frequency of in-hospital death and Q wave MI was similar to that of a matched consecutive series of patients at our institution who underwent emergent CABG after failed angioplasty. At 1 year, the frequency of death, Q wave MI, CABG and severe angina at 1 year was similar in the two groups; the need for repeat percutaneous intervention was more common in the stent group (25% vs. 0%, p = 0.01). CONCLUSIONS: Implantation of multiple, contiguous intracoronary stents was associated with a high initial success rate, although the incidence of early stent closure was relatively high. Adverse events at 6 months of follow-up were more frequent than previously reported for elective single-stent implantation; however, adverse angiographic characteristics such as dissection and thrombus were frequent in this group. In addition, the strategy of multiple stent implantation in the setting of failed angioplasty is a reasonable alternative to emergent CABG, although the need for further percutaneous intervention must be anticipated.

Angioplasty, Balloon, Coronary↗

PubMed1997

The effect of basic fibroblast growth factor on coronary vascular tone in experimental hypercholesterolemia in vivo and in vitro.

OBJECTIVE: To determine whether bFGF causes coronary vasoconstriction in experimental hypercholesterolemia in association with endothelial dysfunction. METHODS: We infused 0.02 microgram/kg per min bFGF into the left anterior descending artery of anesthetized pigs (n = 5) before and after 10 weeks of a high-cholesterol diet. The coronary artery diameter (CAD) was measured by quantitative angiography and the coronary blood flow (CBF) was calculated using coronary-flow Doppler measurements. In additional in-vitro studies, epicardial arteries from normal and hypercholesterolemic pigs were exposed to cumulative concentrations of bradykinin (10(-11)-10(-6) mol/l) after precontraction with 10(-6) mol/l endothelin-1. Cumulative concentrations of bFGF (10(-13)-10(-8) mol/l) were added to other vessels with and without prior contraction with 10(-5) mol/l PGF2 alpha. Similar in-vitro studies were performed using rings from which the endothelium had been removed. RESULTS: In vivo, intracoronary administration of bFGF increased the CBF by 33 +/- 33% and the CAD by 12 +/- 5% at baseline, but reduced the CBF by 45 +/- 8% and the CAD by 14 +/- 6% after 10 weeks of a high-cholesterol diet. In vitro, the endothelium-dependent vasorelaxation in response to bradykinin was attenuated significantly in coronary arteries from hypercholesterolemic pigs (P < 0.05). Cumulative concentrations of bFGF exerted no effect on the coronary epicardial tone both in normal (with and without endothelium) and in hypercholesterolemic pigs. CONCLUSIONS: Acute administration of intracoronary bFGF caused coronary vasodilatation under steady-state conditions and vasoconstriction under diet-induced hypercholesterolemia. In vitro, bFGF did not affect the coronary epicardial tone. These findings suggest that the coronary vasoactive properties of bFGF may be exerted indirectly and are affected by the functional integrity of the endothelium.

Animals↗