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Biomedical subjects

C H McCabe

Publications and source records attributed to C H McCabe.

At least 73 records · Page 4Linked to original sources
PubMed1994

A pilot trial of recombinant desulfatohirudin compared with heparin in conjunction with tissue-type plasminogen activator and aspirin for acute myocardial infarction: results of the Thrombolysis in Myocardial Infarction (TIMI) 5 trial.

OBJECTIVES: The purpose of this study was to assess the value of recombinant desulfatohirudin (hirudin) as adjunctive therapy to thrombolysis in acute myocardial infarction. BACKGROUND: Failure to achieve initial reperfusion and reocclusion of the infarct-related artery remain major limitations of thrombolytic therapy despite aggressive regimens of heparin and aspirin. Hirudin, a direct thrombin inhibitor, has been shown in experimental models to enhance thrombolysis and reduce reocclusion. METHODS: The Thrombolysis in Myocardial Infarction (TIMI) 5 trial was a randomized, dose-ranging, pilot trial of hirudin versus heparin, given with front-loaded tissue-type plasminogen activator and aspirin to 246 patients with acute myocardial infarction. Patients received either intravenous heparin or hirudin at one of four ascending doses for 5 days. Patients underwent coronary angiography at 90 min and at 18 to 36 h, unless rescue angioplasty was performed. RESULTS: The primary end point, TIMI grade 3 flow in the infarct-related artery at 90 min and 18 to 36 h without death or reinfarction before the 18- to 36-h catheterization was achieved in 97 (61.8%) of 157 evaluable hirudin-treated patients compared with 39 (49.4%) of 79 evaluable heparin-treated patients (p = 0.07). All four doses of hirudin led to similar findings in the angiographic and clinical end points. At 90 min, TIMI grade 3 flow was present in 105 (64.8%) of 162 hirudin-treated patients compared with 48 (57.1%) of 84 heparin-treated patients (p = NS). Infarct-related artery patency (TIMI grade 2 or 3 flow) was similar in the two groups (82.1% and 78.6%, respectively). At 18 to 36 h, 129 (97.8%) of 132 hirudin-treated patients had a patent infarct-related artery compared with 58 (89.2%) of 65 heparin-treated patients (p = 0.01). Reocclusion by 18 to 36 h occurred in 2 (1.6%) of 123 hirudin-treated patients versus 4 (6.7%) of 60 heparin-treated patients (p = 0.07). Death or reinfarction occurred during the hospital period in 11 (6.8%) of 162 hirudin-treated patients compared with 14 (16.7%) of 84 heparin-treated patients (p = 0.02). Major spontaneous hemorrhage occurred in 1.2% of hirudin-treated patients versus 4.7% of heparin-treated patients (p = 0.09), and major hemorrhage at an instrumented site occurred in 16.3% and 18.6%, respectively (p = NS). CONCLUSIONS: Hirudin is a promising agent compared with heparin as adjunctive therapy with thrombolysis for acute myocardial infarction, and its evaluation in larger trials is warranted.

Adjuvants, Pharmaceutic↗
PubMed1993

Use of composite endpoints in thrombolysis trials of acute myocardial infarction.

Although preventing early mortality following acute myocardial infarction (MI) is the most important goal of thrombolytic therapy, insistence on its use as the only or principal endpoint in trials of acute MI will limit the number of new thrombolytic-antithrombotic regimens that can be tested, and thus may inhibit future progress of this important area of cardiovascular therapeutics. Trials of thrombolytic therapy over the past decade, as discussed in this article, have demonstrated that: (1) thrombolytic therapy improves both mortality and intermediate endpoints, and (2) intermediate nonfatal endpoints are strongly linked to long-term mortality. Taken together, these facts provide strong evidence that intermediate nonfatal events can be used as valid endpoints in future trials of thrombolytic therapy. The unsatisfactory outcome composite endpoint, which incorporates mortality and important intermediate endpoints, will make it possible to compare innovative new regimens in much smaller trials. Ultimately, both of these approaches (i.e., megatrials using a mortality endpoint and smaller trials utilizing a composite unsatisfactory outcome endpoint) can be used in a complementary fashion. A new regimen could first be tested using the unsatisfactory outcome endpoint; if it showed particular promise, it could then become a candidate for testing in a megatrial. Conversely, if it did not prove better than standard regimens, futile research in tens of thousands of patients might be prevented. Thus, the use of composite endpoints will expand the number of new thrombolytic-antithrombotic regimens that can be tested and, it is hoped, accelerate progress in the treatment of acute MI.

Clinical Trials as Topic↗
PubMed1992

PTCA in the elderly: the "young-old" versus the "old-old".

OBJECTIVE: To evaluate the use of percutaneous transluminal coronary angioplasty (PTCA) in elderly coronary artery disease (CAD) patients. DESIGN: A prospective study of patients 60 years and older undergoing de novo PTCA. We analyze patient risk factors, underlying disease, and clinical outcomes, with at least 3-year follow-up. Comparisons between different age strata among these patients are made to clarify differences between the young old (60 to 69 years), the middle old (70 to 79 years), and the very old (80 years and older). SETTING: Beth Israel Hospital, Boston, both a primary care and tertiary care teaching hospital. PATIENTS: 907 consecutive elderly cardiac patients referred for PTCA are studied. INTERVENTIONS: PTCA's were completed using the newest catheter technologies as they became available. All patients were premedicated with aspirin and dipyridamole, and all were anticoagulated with heparin. RESULTS: Subdivision by age demonstrates that the majority (67%) of patients aged 60 to 69 were males, but females were preponderant (61%) in those aged 80 and older. Octogenarians also had lower incidence of hypercholesterolemia, tobacco use, and family history of CAD, and a higher frequency of CHF, angina, and previous MI. Although total procedure-complications increased with age, critical complications (MI, reocclusion, CABG, death) did not. Primary procedural success was similar in all age strata, but older patients had a higher prevalence of multi-vessel disease and longer hospital stay. Follow-up shows that most patients did well after PTCA; there was no increase in repeat PTCA, CABG, and MI with age. CONCLUSIONS: While advanced age is associated with changes in risk and clinical parameters for CAD patients, age alone is not a reasonable criterion to limit the use of PTCA.

Age Factors↗
PubMed1991

Salvage of branch vessels during bifurcation lesion angioplasty: acute and long-term follow-up.

To evaluate angiographic success, frequency of branch vessel loss and salvage, and long-term outcome, we studied the early and late outcomes of 56 consecutive patients who underwent PTCA of bifurcation lesions, which involved the left anterior descending or left circumflex coronary artery, with stenoses greater than 70% in both the parent and an involved branch vessel. In 35 patients (63%), the PTCA strategy was attempted dilation of both the main vessel and the involved branch vessels using predominantly a double-wire, sequential balloon technique; in 21 (27%) the PTCA attempt was confined to the main vessel alone. Transient angiographic occlusion of the branch vessel occurred in 32% of patients in whom dilation of both vessels was attempted, and in 38% in whom the main vessel alone was dilated (p = NS); 91% of the occluded branch vessels were the salvaged when sequential angioplasty of both vessels had been initially planned, compared to only 38% when the initial strategy had been dilation of the main vessel alone (p less than .05). Predischarge exercise testing showed residual ischemia in 6% of patients who had both vessels successfully dilated, versus 37% in those in whom dilatation was confined to the main vessels (p less than .01). Clinical restenosis, defined as late (greater than 6 weeks) recurrence of angina or a positive exercise test, occurred in 42% of patients who had both vessels successfully dilated. Thus although bifurcation lesion angioplasty frequently results in transient branch vessel loss, these branches can usually be salvaged using a double-wire technique but tend to have a higher late restenosis than conventional single vessel PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1989

Randomised trial of fish oil for prevention of restenosis after coronary angioplasty.

To examine the potential role of fish oil supplementation in the prevention of restenosis after coronary angioplasty (PTCA), a randomised double-blind trial was conducted in 204 patients. The treatment group received 6 g/day of n-3 fatty acids, beginning 5.4 (SD 3.2) days before PTCA, and continuing for 6 months; the control group received olive oil placebo. Compliance was assessed by pill count and plasma levels of eicosapentaenoic acid (EPA). Restenosis was identified by symptoms and exercise testing and confirmed by angiography. PTCA was successful in 186 patients (93%). The incidence of angiographic restenosis was 34% in the fish oil group and 23% in the control group (relative risk 1.7, 95% CI 0.9-3.4). The lack of benefit of fish oil was not influenced by length of pretreatment, compliance with study medication, or the concentrations of plasma EPA achieved.

Angioplasty, Balloon↗
PubMed1989

The role of exercise-induced silent myocardial ischemia in patients with abnormal left ventricular function. A report from the Coronary Artery Surgery Study (CASS) registry.

To evaluate the significance of ischemic ST depression without anginal chest pain (silent ischemia) during exercise testing among patients with abnormal left ventricular function, the data on 121 such patients with proven coronary artery disease (CAD) from the Coronary Artery Surgery Study (CASS) registry were analyzed. The patients with silent ischemia (group 1) were compared to: 124 CAD patients with both ST depression and angina (symptomatic ischemia, group 2); 159 CAD patients with neither ST depression nor angina (no ischemia, group 3); and 37 patients without CAD (controls). Survival at 7 years with medical therapy was similar for groups 1 (55%) and 2 (60%), but was substantially better for group 3 (73%, p = 0.001). Among group 1 patients with silent ischemia, survival was related to the severity of CAD (p = 0.001). Patients with silent ischemia and three-vessel CAD had a poor 7-year survival rate (37%) when treated medically. A comparable but non-randomized group of patients with silent ischemia and three-vessel CAD who underwent coronary artery bypass surgery had a much better 7-year survival rate (83%, p less than 0.0001). These results suggest that among patients with CAD and abnormal left ventricular function, silent ischemia adversely affects survival and can identify a higher risk subset of patients whose survival might be improved after coronary bypass surgery.

Coronary Disease↗
PubMed1988

Risk of developing an acute myocardial infarction or sudden coronary death in patients with exercise-induced silent myocardial ischemia. A report from the Coronary Artery Surgery Study (CASS) registry.

To evaluate whether patients with silent myocardial ischemia during exercise testing are at increased risk for developing a subsequent acute myocardial infarction or sudden death, the data on 424 such patients with proven coronary artery disease (CAD) from the Coronary Artery Surgery Study (CASS) registry were analyzed. These patients (group 1) were compared with 456 other patients with CAD (group 2) who had both ischemic ST depression and angina pectoris during exercise testing and with 1,019 control patients without CAD. The probability of remaining free of a subsequent acute myocardial infarction or sudden death at 7 years was 80 and 91%, respectively, for group 1, 82 and 93%, respectively, for group 2 (difference not significant, compared with group 1), and 98 and 99%, respectively, for the control patients (p less than 0.001), compared with group 1 or 2). Among patients in group 1, the probability of remaining free of myocardial infarction and sudden death at 7 years was related to the severity of CAD and presence of left ventricular (LV) dysfunction, and ranged from 90% for patients with 1-vessel CAD and preserved LV function to 38% for patients with 3-vessel CAD and abnormal LV function (p less than 0.001). Thus, patients with either silent or symptomatic ischemia during exercise testing have a similar risk of developing an acute myocardial infarction or sudden death--except in the 3-vessel CAD subgroup, where the risk is greater in silent ischemia. The risk of patients with silent myocardial ischemia is based primarily on angiographic variables.

Adult↗
PubMed1988

Initial success and long-term follow-up of percutaneous transluminal coronary angioplasty in chronic total occlusions versus conventional stenoses.

Coronary angioplasty was attempted in 1,074 consecutive patients, including 169 patients with total (100%) occlusion (group 1), 102 patients with functional total (99%) occlusion (group 2) and 711 patients with conventional (70 to 95%) stenoses (group 3). After exclusion of 92 patients with acute myocardial infarction, the mean age of the patients was 57 +/- 12 years, including 727 men (74%) and 255 women (26%). Although there were no differences between groups with respect to anginal symptoms or extent of coronary artery disease, the primary success rate (by lesion) varied according to lesion severity, and was 63%, 78% and 90% for groups 1, 2 and 3, respectively (p less than 0.001). Only 3 patients (1%) with chronic coronary artery occlusion (groups 1 and 2) required emergency surgery because of side-branch occlusion in 2 patients and guidewire fracture in 1 patient, whereas emergency surgery was required in 14 patients (2%) in group 3. Long-term follow-up averaging 19 +/- 11 months was available for 95% of patients. Although the combined likelihood of death or nonfatal myocardial infarction was below 6% for each group at 2 years (difference not significant), the likelihood of death, nonfatal infarction, coronary bypass surgery or repeat percutaneous transluminal coronary angioplasty was higher (41%) in group 1 than in groups 2 (28%) or 3 (28%) (p less than 0.001). Thus, coronary angioplasty can be performed safely and effectively in patients with chronic total occlusion, although neither the primary success rate nor the long-term follow-up are as favorable as in patients with conventional stenoses.

Angioplasty, Balloon↗
PubMed1988

Use of percutaneous transluminal coronary angioplasty and bypass surgery despite improved medical therapy for unstable angina pectoris.

To evaluate current strategies for the management of unstable angina, 104 consecutive patients admitted to the coronary care unit with unstable angina during a 6-month period were followed prospectively. Although 58 patients had symptomatic relief with the initiation of intensive medical therapy, 46 (44%) continued to have episodes of angina despite maximal tolerated triple-drug antianginal therapy as well as aspirin or heparin, or both. In-hospital mortality for the 104 patients was 4%. The incidence of myocardial infarction was 8%, and differed (p less than 0.01) for the medically responsive group (3%) vs the medically refractory group (13%). Based on clinical status and coronary anatomy, patients were referred for either bypass surgery (46%), coronary angioplasty (41%) or continued medical therapy (13%). Choice of therapy varied according to the extent of coronary disease, with coronary angioplasty attempted in 72% of patients with 1-vessel disease, 44% of patients with 2-vessel disease and 7% of patients with 3-vessel disease. Angioplasty was performed with an initial success rate of 88%, and compared favorably with bypass surgery in terms of in-hospital mortality (0 vs 11%), late mortality (2.8 vs 7.7%), freedom from angina (62 vs 69%) and subsequent employment (44 vs 27%) at 18 months follow-up. The favorable results of angioplasty in this prospective observational study suggest that additional randomized trials should be conducted in this important patient group.

Adrenergic beta-Antagonists↗
PubMed1988

Predictors, therapeutic options and long-term outcome of abrupt reclosure.

To ascertain the clinical and procedural factors that relate to the occurrence and management of abrupt reclosure, data on 1,160 consecutive patients who underwent coronary angioplasty between December 1981 and December 1986 were analyzed. Abrupt reclosure occurred in 54 patients (4.7%), developing during the dilatation procedure in 43 patients (80%) and delayed by 11 +/- 2 hours after the procedure in 11 patients (20%). Patients were divided into 3 groups based on subsequent management: (1) 22 patients (40%) in whom the involved vessel was reopened by additional dilatation, (2) 14 patients (26%) in whom the involved vessel was not reopened but the patient was treated medically, and (3) 18 patients (33%) in whom abrupt reclosure was managed by emergency bypass surgery, yielding an overall emergency surgery rate of 1.6%. Patients whose abrupt reclosure was reopened were more likely to have luminal thrombus (54 vs 28%) and less likely to have extensive local dissection after dilatation (14 vs 61%; p less than 0.025) than patients undergoing emergency surgery. Patients treated medically despite continued vessel occlusion were more likely to have collateral blood flow to the occluded zone (54 vs 11%, p less than 0.01) than patients undergoing surgery. While 10 of 18 patients (56%) undergoing emergency surgery sustained a myocardial infarction, all patient subgroups appeared to do well during long-term follow-up.

Angioplasty, Balloon↗
PubMed1988

Comparison of coronary artery bypass surgery and medical therapy in patients with exercised-induced silent myocardial ischemia: a report from the Coronary Artery Surgery Study (CASS) registry.

To determine whether coronary artery bypass surgery would prolong survival in patients with silent myocardial ischemia during exercise testing, the data on 692 such patients from the Coronary Artery Surgery Study (CASS) registry were analyzed. The patients were followed up for up to 7 years after medical (n = 424) or surgical (n = 268) therapy. Stratification of patients into subsets was based on the results of cardiac catheterization. Surgical benefit was greatest in the patients with three vessel coronary artery disease or abnormal left ventricular function. Among the 75 patients with three vessel coronary disease and left ventricular dysfunction, the 7 year survival rate was 37% for the medical group and 90% for the surgical group (p less than 0.0001). Thus, among patients with silent myocardial ischemia during exercise testing in this nonrandomized study, survival appeared to be enhanced by coronary artery bypass surgery in subsets of patients with severe coronary artery disease and abnormal left ventricular function.

Coronary Artery Bypass↗
PubMed1987

Value of exercise testing in determining the risk classification and the response to coronary artery bypass grafting in three-vessel coronary artery disease: a report from the Coronary Artery Surgery Study (CASS) registry.

To determine whether exercise testing can identify higher risk patients with 3-vessel coronary artery disease (CAD) whose survival might be prolonged by coronary artery bypass grafting (CABG), the results of CABG were compared with those of medical therapy in 1,249 nonrandomized patients with 3-vessel CAD from the Coronary Artery Surgery Study (CASS) registry who underwent exercise testing. Analysis of 28 variables by Cox's regression model for survival revealed an independent effect of the left ventricular (LV) score, the final exercise stage, and treatment received on survival. Seven-year survival rates between medical and surgical therapy were compared among subsets of patients according to the LV function and the results of exercise testing. Among patients with normal LV function, those with at least 1 mm of ischemic ST-segment depression or low exercise capacity had better 7-year survival if treated by surgical rather than medical therapy (p less than 0.05). Survival was not different between the medical and surgical groups in patients without ischemic ST depression or with good exercise capacity. Among patients with impaired LV function, surgery improved survival in most subsets of patients with the exception of patients with a preserved exercise capacity. These results support the use of exercise testing in the risk stratification of patients with 3-vessel CAD.

Clinical Trials as Topic↗
PubMed1987

Significance of silent myocardial ischemia during exercise testing in patients with coronary artery disease.

To evaluate the significance of ischemic ST-segment depression without associated chest pain during exercise testing, data were analyzed from 2,982 patients from the Coronary Artery Surgery Study (CASS) registry who underwent coronary arteriography and exercise testing and were followed up for 7 years. Patients with proved coronary artery disease (CAD) (at least 70% diameter narrowing) were grouped according to whether they had at least 1 mm of ST-segment depression or anginal chest pain during exercise testing. Four hundred twenty-four had ischemic ST depression without angina (group 1); 232 had angina but no ischemic ST depression (group 2); 456 had both ischemic ST depression and angina (group 3); and 471 had neither ischemic ST depression nor angina (group 4). Sixty-three percent of patients in group 1 and 55% in group 2 had multivessel CAD (difference not significant). The 7-year survival rates were similar for patients in groups 1 (76%), 2 (77%), and 3 (78%), but were significantly better for patients in group 4 (88%, p less than 0.001). Among group 1 patients, survival was related to severity of CAD (p less than 0.001). The 7-year survival rate in group 1 was significantly worse than that in a separate group of 282 patients with ischemic ST depression without angina during exercise testing who had no CAD (95% survival, p less than 0.001). Thus, in patients with silent myocardial ischemia during exercise testing, the extent of CAD and the 7-year survival rate are similar to those of patients with angina during exercise testing. Prognosis is determined primarily by the severity of CAD. In patients without CAD, the survival rate is excellent.

Angina Pectoris↗
PubMed1987

Incidence and management of limb ischemia with percutaneous wire-guided intraaortic balloon catheters.

In 103 patients who underwent placement of 106 percutaneous wire-guided intraaortic balloon catheters between August 1983 and January 1986, all placements were successful and the average duration of counterpulsation was 3.4 +/- 1.6 days. During counterpulsation, 45 patients developed limb ischemia that required premature balloon removal in 29 patients. The development of limb ischemia was significantly related to the presence of diabetes (risk ratio 2.0), peripheral vascular disease (risk ratio 1.9), female gender (risk ratio 1.8) and the presence of a postinsertion ankle-brachial pressure index less than 0.8 (risk ratio 7.9). There was no association between the development of limb ischemia and age, body surface area, balloon size (10.5F/12F) or adequacy of anticoagulation. Fifteen patients underwent vascular surgery for treatment of balloon-related limb ischemia, which was associated with one operative death. Nine patients had persistent limb ischemia (seven asymptomatic, two symptomatic) at the time of hospital discharge. Improvements in wire-guided balloon technology have increased the probability of successful balloon placement over that of surgical placement and have reduced the incidence of major aortic injury, but there is no evidence that these improvements have reduced the incidence of limb ischemia or its sequelae. This should be borne in mind before proceeding with balloon insertion in patients with one or more risk factors for developing limb ischemia.

Aged↗
PubMed1986

The role of exercise testing in identifying patients with improved survival after coronary artery bypass surgery.

To determine whether exercise testing can identify patients whose survival might be prolonged by coronary artery bypass surgery, the results of bypass surgery were compared with those of medical therapy alone in 5,303 nonrandomized patients from the Coronary Artery Surgery Study registry who underwent exercise testing. Patients in the two treatment groups differed substantially with regard to important baseline variables. Analysis of 32 variables by Cox's regression model for survival revealed an independent beneficial effect of bypass surgery on survival (p less than 0.00001). Patients were then stratified into subsets according to the results of exercise testing. Surgical benefit was greatest in the 789 patients who exhibited at least 1 mm of ST segment depression and who could exercise only into stage 1 or less. Among the 398 patients with three vessel coronary disease showing these characteristics, 7 year survival was 58% for the medical group and 81% for the surgical group (p less than 0.001). There was no difference in survival between the surgical and medical groups among the 1,545 patients without ischemic ST segment depression who were able to exercise into stage 3 or greater. Thus, in patients who demonstrate ischemia on exercise testing and whose exercise capacity is limited, coronary bypass surgery appears to improve survival in comparison with medical therapy alone.

Coronary Artery Bypass↗
PubMed1986

The influence of surgery on the natural history of angiographically documented left ventricular aneurysm: the Coronary Artery Surgery Study.

Coronary artery bypass surgery with or without aneurysmectomy has been used to treat patients with angiographically defined left ventricular aneurysm. To evaluate whether surgery benefits such patients, we analyzed the data from 1131 patients who were enrolled in the registry of the Coronary Artery Surgery Study. Four hundred sixty-seven patients underwent bypass surgery, of which 238 also had left ventricular resection, and 30 had resection alone. The overall operative mortality was 7.9%; the operative mortality was 7% for bypass alone compared with 9% for bypass surgery plus left ventricular resection (NS). Long-term survival by life-table analysis was similar for both medically and surgically treated patients (69% vs 67%, respectively). Cox survival analysis identified congestive heart failure score, duration of chest pain, extent of coronary disease, left ventricular end-diastolic pressure, age, and surgical therapy as important predictors of outcome. Patient subsets that showed improved survival with surgical therapy after adjustment for inequities in baseline characteristics were patients with three-vessel disease and those patients in moderate- and high-risk subgroups. Surgical therapy significantly reduced symptoms of angina and use of cardiac medications but the incidence of recurrent infarction was similar for both therapies.

Age Factors↗