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Biomedical subjects

H C Herrmann

Publications and source records attributed to H C Herrmann.

At least 37 records · Page 2Linked to original sources
PubMed1997

Comparison of outcome after stenting for de novo versus restenotic narrowings in native coronary arteries.

Intracoronary stenting of de novo narrowings results in a lower restenosis rate when compared with percutaneous transluminal coronary angioplasty. We sought to determine whether intracoronary stenting for restenotic narrowings is associated with a worse outcome when compared with stenting for de novo narrowings. A total of 114 consecutive patients with 124 narrowings were retrospectively identified. Stents were deployed in 46 de novo (37%) and in 78 restenotic (63%) narrowings. The 2 groups were similar with respect to variables known to affect restenosis. Follow-up angiograms were available in 88% of patients at a mean of 6.3 +/- 3.3 months after stent implantation. At follow-up angiography, a significantly higher restenosis rate in the restenotic group was observed (p = 0.05). Restenosis risk could not be predicted from variables known at the time of stent implantation. However, the presence of angina at the time of follow-up was significantly associated with restenosis (p = 0.01). Kaplan-Meier survival curves for freedom from repeat target-site revascularization demonstrated a significant difference in the need for target-site revascularization between the de novo and restenotic groups over the first-year post-stent implantation (p = 0.01; relative risk = 1.94). Multivariate analysis identified restenosis as the indication for stenting (p <0.01), postprocedure percent stenosis (p = 0.01), and narrowing length (p = 0.01) as independent predictors for repeat target-site revascularization. When compared with de novo narrowings, restenotic narrowings have a worse outcome after stenting. A prospective, randomized trial comparing outcome after percutaneous transluminal coronary angioplasty and stents for restenotic narrowings would be useful.

Adult↗
PubMed1997

Tirofiban: an investigational platelet glycoprotein IIb/IIIa receptor antagonist.

The deposition of a platelet rich thrombus on an atherosclerotic plaque is a critical step in the development of unstable coronary syndromes. Currently available therapeutic agents such as aspirin and ticlopidine are relatively weak inhibitors of platelet aggregation. Recently, antagonists to platelet glycoprotein IIb/IIIa (GPIIb/IIIa), a platelet surface integrin whose activation and subsequent binding to fibrinogen is the final common step in the formation of platelet aggregates, have been utilised to treat unstable angina and myocardial infarction. Tirofiban is a novel, specific, low molecular weight GPIIb/IIIa receptor antagonist, which competitively inhibits the platelet fibrinogen receptor. Tirofiban is administered as an intravenous infusion with a mean half-life of 1.6 h. In healthy volunteers, the plasma concentration and half-life of tirofiban are unaffected by pre-treatment with aspirin, although aspirin increases the bleeding time prolongation caused by tirofiban. Tirofiban is excreted by both renal (37%) and non renal mechanisms. Three clinical trials, PRISM, PRISM PLUS, and RESTORE, have evaluated the safety and efficacy of tirofiban in unstable angina and in high-risk percutaneous transluminal coronary angioplasty (PTCA). When compared to heparin in the management of unstable angina, tirofiban decreased the odds of recurrent ischaemia, myocardial infarction, or death by 36% at 48 h, and death by 39% at 30 days. Similarly, the addition of tirofiban to heparin reduced the odds of recurrent ischaemic events for death at 7 days by 34%. RESTORE, a clinical trial evaluating the efficacy and safety of tirofiban in patients undergoing PTCA within 72 h of presentation with unstable angina or myocardial infarction, demonstrated a 38% reduction in a composite end-point at 48 h; the need for urgent PTCA and coronary artery bypass graft (CABG) at 30 days was reduced by 36%. Adverse side-effects, including major bleeding, were not significantly higher with tirofiban treatment. Tirofiban and other GPIIb/IIIa inhibitors represent a major advance in the treatment of unstable coronary syndromes and high-risk PTCA.

Journal Article↗
PubMed1996

Hemodynamic assessment of patients with low-flow, low-gradient valvular aortic stenosis.

In aortic stenosis (AS), conventional indexes of severity vary with changes in transvalvular flow. It is important to determine the true severity of obstruction because AS in the presence of low cardiac output and low gradient is associated with high mortality during aortic valve replacement. This study compares 3 indexes of stenosis severity at different transvalvular flow rates in patients with low-flow, low-gradient critical AS. Eight patients with critical AS (valve area < or = 0.7 cm2), low cardiac output (< 4.0 L/min), and low mean transvalvular gradient (< or = 40 mm Hg) underwent hemodynamic assessment at baseline, after transvalvular flow was augmented with dobutamine, and after the valve opening was increased with percutaneous balloon aortic valvuloplasty. Severity of obstruction was assessed using 3 different measures: Gorlin formula calculated valve area, valvular resistance, and percentage left ventricular stroke work loss. Dobutamine infusion increased cardiac output by 35% and mean transvalvular gradient by 27%. The mean Gorlin formula calculated aortic valve area increased from 0.5 to 0.6 cm2 (p = 0.002). Percentage left ventricular stroke work loss increased from 23% to 28% (p = 0.03). Valve resistance was unchanged by dobutamine (350 to 310 dynes X sec X cm(-5); p = NS). Balloon valvuloplasty increased cardiac output 13% and decreased the gradient 31%; this resulted in an increase in the calculated valve area from 0.6 to 0.9 cm2 (p = 0.001). Percentage left ventricular stroke work loss decreased from 28% to 20% (p = 0.002), and valve resistance decreased from 310 to 181 dynes X sec X cm(-5) (p = 0.001) after valvuloplasty. We conclude that in patients with low-flow, low-gradient critical AS, valve resistance is the most flow-independent measure of severity of stenosis. All measures improve with percutaneous balloon aortic valvuloplasty.

Aged↗
PubMed1996

Radiation-induced cardiovascular dysfunction.

Coronary artery disease and valvular dysfunction are long-term complications of mediastinal irradiation. We describe 3 patients who underwent successful combined coronary artery bypass grafting and valve replacement for symptoms related to radiation-induced coronary artery and valvular disease.

Adult↗
PubMed1996

Randomized, double-blind, placebo-controlled dose-ranging study of tirofiban (MK-383) platelet IIb/IIIa blockade in high risk patients undergoing coronary angioplasty.

OBJECTIVES: The objectives of this double-blind, placebo-controlled, randomized dose-ranging study were 1) to examine the safety and tolerability of tirofiban (MK-383), a new nonpeptide platelet IIb/IIIa receptor antagonist, on a background of intravenous heparin and aspirin therapy; 2) to study the pharmacodynamics and pharmacokinetics of tirofiban; and 3) to evaluate the incidence of adverse cardiac outcomes (urgent repeat revascularization, myocardial infarction and death) with tirofiban versus placebo in a high risk subset of patients undergoing coronary angioplasty. BACKGROUND: Abrupt vessel closure complicates 4% to 8% of angioplasty procedures. Recent data have suggested that agents that antagonize the platelet glycoprotein IIb/IIIa receptor may reduce the incidence of adverse ischemic outcomes after coronary angioplasty. METHODS: Seventy-three patients received tirofiban in three sequential dose panels and 20 patients received placebo. Patients within each panel were randomized to receive either tirofiban or placebo in a 3:1 randomization design. Bolus doses of 5, 10 and 10 microg/kg and continuous infusion (16 to 24 h) doses of 0.05, 0.10 and 0.15 microg/kg per min were administered in panels I, II and III, respectively. Patients received concomitant heparin and aspirin for the angioplasty procedure. Data on patients receiving placebo (heparin and aspirin only) were pooled across panels for comparisons. The pharmacodynamic effect of tirofiban on ex vivo platelet aggregation to 5 micromol/liter adenosine diphosphate (ADP) and bleeding times were measured. Clinical outcomes were assessed in all patients, but the power to detect clinically meaningful differences (a one-third reduction in clinical events) between groups was limited (5%). RESULTS: Tirofiban was associated with a dose-dependent inhibition of ex vivo ADP-mediated platelet aggregation that was sustained during intravenous infusion and resolved rapidly after drug cessation. Adverse bleeding events, largely related to vascular access site hemorrhage, were slightly increased at the highest dose. Adverse clinical outcomes were infrequent in all patients and were not different among the small number of patients within each group. CONCLUSIONS: This study establishes a rational and generally well tolerated dosing regimen for administration of tirofiban as adjunctive therapy in high risk angioplasty patients. The impact of tirofiban on adverse clinical outcomes after angioplasty awaits definition by a larger clinical trial.

Angioplasty, Balloon, Coronary↗
PubMed1996

Three-year clinical follow-up after Palmaz-Schatz stenting.

OBJECTIVES: Our goals were to examine late clinical outcome in a cohort of patients who electively received Palmaz-Schatz intracoronary stents, to identify specific predictors of outcome and to determine the time course of the development of ischemic cardiac events after stenting. BACKGROUND: Short-term results of Palmaz-Schatz intracoronary stenting have been promising, with a reduction in both angiographic restenosis and clinical cardiac events up to 1 year after stenting. METHODS: We analyzed the clinical outcomes in 65 consecutive patients who underwent stenting at least 3 years before analysis. Demographic, clinical and procedural predictors of survival and event-free survival, defined as freedom from myocardial infarction, stent-site percutaneous transluminal coronary angioplasty, coronary artery bypass graft surgery or death, were analyzed at a mean follow-up of 39 +/- 17 months. RESULTS: Absolute survival and event-free survival at 3 years were 88% and 56%, respectively. Three-year freedom from stent-site revascularization was 66%. Predictors of decreased long-term survival (p < 0.05) included diabetes and a high angina score (Canadian Cardiovascular Society class III/IV) at 6 and 12 months after stenting. Predictors of decreased event-free survival (p < 0.05) included a high angina score at 3, 6 and 12 months after stenting, smaller stent deployment balloon size and greater number of stents implanted. Freedom from adverse events by 6 months after stenting also correlated with long-term event-free survival. Eighty-five percent of stent-site revascularizations occurred within 1 year. During late follow-up (>24 months), no patients had stent-site stenoses requiring revascularization, whereas 11% of patients required revascularization in nonstented coronary segments. CONCLUSIONS: Clinical predictors of worse long-term outcome included diabetes mellitus, higher angina score at follow-up, smaller stent deployment balloon size and greater number of stents at implantation. During follow-up, the majority of adverse events and stent-site revascularizations occurred early after stenting, and disease progression in nonstented vessels accounted for the majority of late revascularization events.

Aged↗
PubMed1995

Long-term outcome of cardiac surgery in patients with mitral stenosis and severe pulmonary hypertension.

BACKGROUND: Pulmonary hypertension increases perioperative risk in patients having mitral valve replacement, but most studies have included patients with mixed mitral valve disease and have not examined long-term outcome. METHODS AND RESULTS: We retrospectively examined the results and predictors of outcome of cardiac surgery in 43 patients (age, 62 +/- 13 years [mean +/- SD]; 81% women) with a primary diagnosis of mitral stenosis and severe pulmonary hypertension (pulmonary artery systolic pressure > or = 60 mm Hg or mean pressure > or = 50 mm Hg). Patients with more than mild mitral regurgitation were excluded. Thirty-eight patients (88%) were in NYHA functional class III or IV, and 11 patients (26%) had an acute presentation requiring urgent surgery. Preoperative hemodynamics demonstrated a mean mitral valve area of 0.7 +/- 0.3 cm2, mean pulmonary artery pressure of 50 +/- 9 mm Hg, and pulmonary artery systolic pressure of 81 +/- 18 mm Hg. Other characteristics included right ventricular failure (18 patients), coronary artery disease (16 patients), and critical aortic stenosis (11 patients). Forty patients underwent mitral valve replacement with St Jude prostheses; 3 had open commissurotomy. Additional surgical procedures included aortic valve replacement (42%), coronary artery bypass graft surgery (26%), and tricuspid valvuloplasty (16%). There were 5 perioperative deaths (11.6%), and 7 other patients (16%) had major complications, including reoperation for hemorrhage, stroke, respiratory failure, myocardial infarction, or a > 30-day hospitalization. Univariate analysis of demographic, hemodynamic, and operative characteristics identified the following predictors of perioperative death (P < .05): acute presentation, clinical evidence of right ventricular failure, impaired left ventricular ejection fraction, and increased left ventricular diastolic pressure. Predictors of complications (P < .05) were acute presentation, ECG evidence of right ventricular hypertrophy, and elevated right ventricular systolic pressure. Multivariate analysis showed only acute presentation and right ventricular hypertrophy as predictors of perioperative death or major complications, respectively. Five- and 10-year actuarial survivals were 80% and 64%, respectively. The only predictor of long-term mortality was advanced age. Functional NYHA status was improved by one grade or more in 76% of survivors. CONCLUSIONS: Patients referred to a tertiary care hospital in the United States with mitral stenosis and severe pulmonary hypertension often have other associated cardiac diseases and comorbid conditions. Cardiac surgery can be successfully performed with an acceptable mortality, and risk factors for poor perioperative outcome can be identified by preoperative clinical characteristics. Younger patients have the best long-term survival, and most survivors experienced long-term improvement in functional status.

Adult↗
PubMed1995

Patient selection reduces thrombotic complications of emergent stenting for failed PTCA.

A comparison of consecutive initial and later patients receiving emergent coronary artery stents to salvage failed PTCA procedures was made to determine whether experience with this procedure can improve patient outcome. Twenty-six consecutive patients underwent emergent, unplanned implantation of one or more Palmaz-Schatz coronary stents at our institution over a 3-1/2 year period. Indications for stent insertion included impending vessel closure (decrease in TIMI flow grade and clinical evidence of ischemia) or acute occlusion (TIMI flow grade 0 or 1 and > or = 99% stenosis) after PTCA. Immediate and final success (30 day) were determined, and the results in the first (Initial) 13 patients were compared to the remaining (Later) 13 patients. Baseline characteristics of the study population included a male predominance (69%) with a mean (+/- SD) age of 57 +/- 10 years. Conventional balloon PTCA was performed in all three native coronary arteries with an increase in mean percentage stenosis from 76 +/- 13 to 85 +/- 14% (P < 0.05). Twelve patients developed acute occlusion and 14 patients impending closure after PTCA due to the appearance of thrombus (12%), dissection (46%), or both (35%). Palmaz-Schatz stents were successfully inserted in all patients restoring TIMI grade 3 antegrade flow; however, major complications developed in almost 50% of patients. Comparison of initial and later patients showed no differences in demographic or pre-PTCA angiographic characteristics. Later patients had less severe stenoses post-PTCA (before stenting) and were less likely to have thrombus present at the angioplasty site (15% vs. 77%, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Inoue balloon mitral valvotomy in patients with severe valvular and subvalvular deformity.

OBJECTIVES: This study evaluated the immediate and long-term results of percutaneous Inoue balloon mitral valvotomy in patients with severe valvular and subvalvular deformity. METHODS: We reviewed the prevalvotomy transthoracic echocardiograms of patients from the North American multicenter Inoue registry with total Massachusetts General Hospital (MGH) echocardiographic scores > or = 10. The echocardiograms were rescored by two investigators to assess valvular and subvalvular morphology to eliminate interinstitutional variability. Ninety patients were originally assigned scores > or = 10. After rescoring, 18 patients (20%) were eliminated, leaving 72 study patients. RESULTS: Balloon mitral valvotomy was technically successful in 69 (96%) of the 72 patients. Mean (+/- SD) mitral valve area increased from 0.9 +/- 0.3 to 1.5 +/- 0.5 cm2. An immediate optimal result, defined as > or = 50% increase in mitral valve area or a final area > or = 1.5 cm2 with no major complications, was achieved in 46 patients (64%). End points for clinical follow-up (events) included mitral valve replacement, repeat valvotomy or death. At a mean follow-up of 22.9 +/- 11.0 months, 22 patients (31%) required mitral valve replacement or a second valvotomy, 9 patients (13%) died, and 32 patients (45%) were in New York Heart Association functional class I or II. Univariate predictors of an immediate optimal result included sinus rhythm, male gender and a lower University of Southern California commissural calcium score. Only sinus rhythm predicted an optimal result by multivariate analysis. Actuarial 3-year event-free survival was 42%. Univariate predictors of event-free survival were a lower grade of mitral regurgitation, lower MGH total echocardiographic score, lower MGH leaflet thickness subscore and lower prevalvotomy left ventricular systolic pressure. Only grade of mitral regurgitation after valvotomy predicted event-free survival by multivariate analysis. CONCLUSIONS: Inoue mitral valvotomy in patients with severe valvular and subvalvular deformity has a high technical success rate and good immediate hemodynamic result but a high cardiovascular event rate in follow-up. Mitral valve replacement should be considered in surgical candidates with an MGH total echocardiographic score > or = 10 because it may be able to provide better long-term event-free survival. Balloon valvotomy remains a reasonable palliative therapeutic option for some patients with severe valvular deformity and high surgical risk.

Actuarial Analysis↗
PubMed1994

Treatment of malignant pericardial effusion.

OBJECTIVE: To discuss the diagnosis and treatment of malignant pericardial effusion and focus on quantitating the success and complication rates of the many treatment modalities and updating recent advances in the field. DATA SOURCES: English-language publications were identified by a computerized search (MEDLINE) of these key words: cancer, tumor, malignancy, pericardium, and pericardial effusion. This computerized search was supplemented by a manual search of the bibliographies of original research articles and textbooks. STUDY SELECTION: Studies were included if the outcome of patients undergoing treatment for malignant pericardial effusion was reported separately from the outcome of patients with other causes of pericardial effusions. Studies that only reported the combined results of patients with malignant and nonmalignant effusions were excluded. DATA EXTRACTION: To determine success rates for the various treatment modalities, we examined freedom from symptomatic recurrence of pericardial effusion requiring reintervention as the key end point. Where appropriate, we also examined procedural mortality rates. RESULTS: Initial relief of symptoms is achieved in most cases with percutaneous pericardiocentesis that, with echocardiographic guidance, can be performed with low morbidity and mortality. In many cases, drainage for several days with an indwelling catheter alleviates the effusion without subsequent recurrence. Systemic antitumor therapy with chemotherapy or radiation therapy is effective in controlling malignant effusions in cases of sensitive tumors such as lymphomas, leukemias, and breast cancer. Local sclerotherapy with tetracycline hydrochloride or bleomycin sulfate is also effective and associated with low morbidity. Sclerotherapy with other agents or radionuclides offers no advantages. Of the several surgical options, subxiphoid pericardiotomy has the advantage of low morbidity and mortality, can often be performed under local anesthesia, and is highly effective in preventing recurrence. Percutaneous balloon pericardiotomy has recently been described. This intervention is performed with local anesthesia, is effective in preventing reaccumulation, and has a low morbidity. CONCLUSIONS: Treatment of malignant pericardial effusions must be individualized with consideration given to the patient's condition and tumor type, the success rates and risks of the various modalities, and local availability and expertise.

Antineoplastic Agents↗
PubMed1994

Comparison of results of intracoronary stenting in patients with unstable vs. stable angina.

Percutaneous transluminal coronary angioplasty (PTCA) has higher complication and restenosis rates when performed in the setting of unstable angina. Balloon-expandable intracoronary stenting is a new technique with the potential to improve the results of PTCA. In order to determine whether stenting is associated with a poorer outcome in patients with unstable angina, we retrospectively examined our experience with the Palmaz-Schatz balloon-expandable intracoronary stent in 105 patients. Patients were divided into 2 groups on the basis of symptoms at the time of stent insertion: group I (n = 57) had stable angina pectoris, and group II (n = 48) had unstable angina defined as pain at rest despite antianginal therapy (Braunwald class II, III). Initial (30-d) and final (6-mo) success rates were defined as stent insertion without myocardial infarction, need for bypass surgery, death, and significant angina. Baseline characteristics were similar, although the patients with unstable symptoms were older, more likely to be female, and had a higher incidence of postinfarction angina. A total of 136 stents were successfully delivered to 97 target sites in 92% of patients. Major complications occurred in 4 patients (4%) and were due to subacute thrombosis in 3 of them. There were no differences in complication rates between patients receiving stents electively with stable vs. unstable symptoms (2% vs. 6%, p = NS). Six-mo. follow-up status was ascertained in 96% of patients and revealed overall clinical success in 83% with angiographic restenosis (> or = 50% stenosis) in 28% of patients. There were no significant differences between groups in rates of restenosis, follow-up angina class, or overall clinical success.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Left ventricular assist without thoracotomy: clinical experience with the Dennis method.

A method to provide left ventricular circulatory assistance without thoracotomy was developed and implemented in 2 patients. The left atrium is cannulated from the neck by passing a catheter across the interatrial septum (Dennis technique) using fluoroscopic and echocardiographic imaging. To facilitate ambulation, the arterial catheter is connected to the right axillary artery. Left atrial to axillary arterial flow is produced by a centrifugal pump. Two patients were perfused at 2.7 to 3.5 L/min for 5 and 6.5 days. One patient had successful coronary angioplasty during perfusion and remains alive 1 year later. The other patient died of sepsis and anuria that preceded implementation of circulatory assistance. The Dennis method of continuous left ventricular circulatory assistance avoids thoracotomy, requires a minimal operation, is portable and inexpensive, uses widely available equipment, and is particularly suitable for patients in cardiogenic shock after acute myocardial infarction. The method is safe and cost-effective, and merits wider application in selected patients.

Angioplasty, Balloon, Coronary↗
PubMed1994

Effects of atrial natriuretic peptide on left ventricular function in hypertension.

Atrial natriuretic peptide (ANP) has natriuretic and vasodilator actions that lower arterial pressure and may be beneficial to hypertensive patients. To assess the effects of ANP on left ventricular function in patients with hypertension, we compared it with the pure vasodilator nitroprusside. Simultaneous left ventricular micromanometer pressure and radionuclide volume were obtained at baseline, during nitroprusside infusion, during a second baseline period, and during ANP infusion in 10 patients with hypertension. Mean arterial pressure fell during ANP and nitroprusside. Heart rate and plasma norepinephrine levels increased by similar amounts during the two agents, whereas cardiac index and stroke volume index were unchanged during both. Peak positive left ventricular dP/dt fell similarly during ANP and nitroprusside, but left ventricular dP/dt at a developed pressure of 40 mm Hg, a less load-dependent index of contractility, was unchanged during both. The relation between end-systolic pressure and volume during ANP infusion was not shifted leftward or rightward from that during nitroprusside infusion, indicating no inotropic effect. Both ANP and nitroprusside shortened at time constant of isovolumic relaxation calculated by the logarithmic method but did not change the time constant calculated by the derivative method. Peak filling rate was unchanged from baseline during both agents. ANP did not shift the end-diastolic pressure-volume point away from the relation constructed from baseline and nitroprusside points. We conclude that ANP has no direct effect on myocardial contractile or diastolic function in patients with hypertension.

Adult↗