Biomedical subjects
J M Gore
Publications and source records attributed to J M Gore.
The impact of age on the incidence and prognosis of initial acute myocardial infarction: the Worcester Heart Attack Study.
As part of a community-wide study examining time trends in the incidence and case-fatality rates (CFR) of patients hospitalized with acute myocardial infarction (MI) in sixteen hospitals in the Worcester, Massachusetts metropolitan area, the association of age to the incidence rates of initial acute MI and to in-hospital and long-term survival among 2115 patients with validated acute MI was examined. After selected age-specific changes in the incidence rates of initial events of acute MI between 1975 and 1981, the incidence rates of acute MI markedly declined between 1981 and 1984, resulting in decreases in the age-specific incidence rates of initial acute MI between 1975 and 1984. For the combined study periods, the in-hospital CFR of acute MI increased from 5.0% in patients less than 55 years of age to 7.9% in those 55 to 64 years, to 16.1% in those 65 to 74 years and to 32.1% in patients 75 years of age and older. Among discharged hospital survivors, increasing age was related to poorer long-term survival over a 5-year follow-up period. The results of this population-based study reinforce the need for, and importance of, modification of coronary risk factors in both young and older individuals, and of focused therapeutic efforts to salvage jeopardized myocardium in elderly patients hospitalized with acute MI.
Postinfarction unstable angina. Pathophysiologic basis for current treatment modalities.
Unstable angina is an acute coronary syndrome characterized by the rapid progression of clinical symptoms which may culminate in acute myocardial infarction, infarct extension or sudden death. The pathologic substrate involves atherosclerotic plaque rupture with platelet deposition, thrombus formation and coronary arterial spasm. Patients with postinfarction angina represent a high-risk subgroup with severe multivessel disease, compromised collateral vessels and/or partially occlusive thrombi; their risk of infarct extension and death is significantly increased. Initial therapy includes nitrates, beta-adrenergic blockers, calcium channel antagonists, aspirin and possibly i.v. heparin, as well as prompt identification and control of exacerbating factors. Thrombolytic therapy may assume a more central role based on its ability to achieve rapid clinical stabilization. Percutaneous transluminal coronary angioplasty and coronary artery bypass grafting may be used emergently in patients refractory to medical therapy, or electively when clinically indicated.
Rapid resolution of acute cor pulmonale with recombinant tissue plasminogen activator.
A case of massive pulmonary embolism complicated by acute cor pulmonale and shock is presented. The IV administration of recombinant tissue-type plasminogen activator (rt-PA) was associated with prompt reversal of clinical, ECG, and nuclear radiographic findings. The role of thrombolytic therapy with rt-PA for massive pulmonary embolism associated with hemodynamic decompensation deserves further investigation.
Bilateral brachial artery emboli presenting as aortic dissection.
Loss of peripheral pulses in a patient with chest pain suggests the diagnosis of aortic dissection. An 80-year-old woman presented with an episode of chest pain and acute bilateral loss of upper extremity pulses that was initially treated as aortic dissection. Findings of physical examination and echocardiography were consistent with mitral stenosis. Angiography revealed bilateral brachial artery emboli, which were treated by embolectomy. To our knowledge, this case represents the first report of simultaneous brachial artery emboli in association with mitral stenosis.
Feasibility and safety of emergency interhospital transport of patients during early hours of acute myocardial infarction.
The transfer of patients with acute myocardial infarction from community hospitals to tertiary care facilities for further intervention has become increasingly more frequent due to the emerging role of thrombolytic therapy and percutaneous transluminal coronary angioplasty. To assess the feasibility and safety of early transfer, a prospective analysis of 57 patients who were transported by ground ambulance or helicopter to the University of Massachusetts Medical Center, Worcester, for acute intervention during the early hours of myocardial infarction was conducted. Before transport, the majority (46 [81%]) of patients were having chest discomfort, 13 (23%) were hypotensive, and 12 (21%) were electrically unstable (defined as high-grade ventricular ectopia or nonsustained ventricular tachycardia). During transport, the majority (41 [72%]) continued to have some chest discomfort; however, only two (4%) remained hypotensive. Although five patients (9%) were electrically unstable during transport, the instability was considered noncritical. The distance traveled or the mode of transportation did not adversely impact on these clinical complications. All patients survived transport, and 53 patients (93%) were eventually discharged from the receiving hospital.
Six- and twelve-month follow-up of the phase I Thrombolysis in Myocardial Infarction (TIMI) trial.
The Thrombolysis in Myocardial Infarction (TIMI) trial Phase I was designed to compare the efficacy and side effects of intravenous recombinant tissue-type plasminogen activator (rt-PA) and intravenous streptokinase (SK) in patients with acute myocardial infarction (AMI). As previously reported, rt-PA led to a reperfusion rate of 62% of totally occluded coronary arteries compared with 31% for SK (p less than 0.001). This study was not designed to determine if intravenous thrombolytic therapy decreases the mortality of AMI; however, the findings in these patients after 1 year of follow-up do permit certain insights into the impact of early reperfusion and reocclusion on the clinical course of patients with AMI. The mortality rate at 6 and 12 months was not significantly different in patients treated with rt-PA compared with SK (7.7% and 10.5% rt-PA vs 9.5% and 11.6% for SK). The frequency of recurrent AMI, coronary artery bypass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA) was similar in the 2 treatment groups. There was no significant difference in 6- and 12-month mortality or in the rate of recurrent AMI in patients who received thrombolytic therapy before compared with after 4 hours of the onset of AMI symptoms. When the results were analyzed on the basis of the patency of the infarct-related artery, irrespective of thrombolytic agent used, for those patients with patent arteries 90 minutes after the initiation of therapy, there was a trend toward a lower 6-month (5.6% vs 12.5%) and 12-month mortality (8.1% vs 14.8%) (p = 0.07).(ABSTRACT TRUNCATED AT 250 WORDS)
Impact of thrombolytic therapy on left ventricular mural thrombi in acute myocardial infarction.
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The efficacy of the addition of nifedipine in patients with mixed angina compared to patients with classic exertional angina: a multicenter, randomized, double-blind, placebo-controlled clinical trial.
Episodes of myocardial ischemia in patients with coronary artery disease may be due to transient increases in coronary vasomotor tone superimposed on a fixed atherosclerotic obstruction. The purpose of this study was to determine whether identification of the clinical pattern of angina could predict the therapeutic response to the addition of nifedipine to a regimen of beta blockers and/or long-acting nitrates. Seventy-two patients with stable exertional angina were divided into two groups: "classic exertional angina" (17 patients), defined as exertional angina with a stable threshold; and "mixed angina" (55 patients), defined as exertional angina provoked by a variable threshold and/or at least two episodes of rest angina within the 3 months prior to screening. Patients were studied with nifedipine and placebo in a 6-week, double-blind, crossover design that used serial anginal diaries, exercise treadmill tests, and 24-hour ambulatory ECG monitoring. In patients with mixed angina, nifedipine reduced the frequency of angina compared to that during placebo treatment (13.1 vs 9.9 episodes/3 weeks, p less than 0.01) and reduced nitroglycerin consumption (11.7 vs 7.5 tablets/3 weeks, p less than 0.05); while in patients with classic exertional angina, nifedipine had no symptomatic effect (7.9 vs 6.8 anginal episodes/3 weeks, NS; 6.4 vs 5.8 nitroglycerin tablets/3 weeks, NS). Patients in both groups experienced a significant decrease in the manifestations of ischemia during exercise testing. Patients with mixed angina experienced a reduction in the daily frequency of painful episodes of ST segment depression during nifedipine treatment compared to placebo (0.6 vs 0.2 episodes, p less than 0.05), but there was no effect on the frequency of episodes of silent ischemia (4.2 vs 3.4 episodes, NS). In patients with classic exertional angina, the addition of nifedipine had no effect on any measure of ambulatory ischemia. We conclude that patients with mixed angina are more likely to benefit symptomatically from the addition of nifedipine therapy than patients with classic exertional angina. The lack of a consistently preferential response to nifedipine in patients with mixed angina, however, suggests that episodic coronary vasoconstriction may not be the only mechanism responsible for ischemia in these patients, and/or that nifedipine may not necessarily provide additional therapeutic benefit beyond that conferred by a regimen of beta blockers and/or nitrates.
Rupture of the interventricular septum complicating acute myocardial infarction: a multicenter analysis of clinical findings and outcome.
Acute ventricular septal rupture in the setting of acute myocardial infarction continues to present clinicians with a difficult therapeutic dilemma. The role of surgical intervention and its timing remains unresolved. A collaborative study from three institutions was undertaken to examine various clinical outcomes in 46 patients with ventricular septal rupture. No medically treated patient survived hospitalization. Since only surgically treated patients survived, we focused our evaluation on those characteristics that might differentiate surgical survivors from surgical nonsurvivors. Systolic blood pressure, pulse, mean right atrial pressure, left ventricular systolic pressure, and cardiopulmonary bypass time were univariate predictors of hospital survival. Multivariate analysis revealed that systolic blood pressure, right atrial pressure, and cardiopulmonary bypass time were strongly predictive of survival (p less than 0.05). In addition, taken together systolic blood pressure and right atrial pressure identified a group of persons who wee much more likely to survive surgical intervention. The results of this study may prove useful in predicting the risk of surgical repair in patients with ventricular septal rupture.
Incidence and case fatality rates of acute myocardial infarction (1975-1984): the Worcester Heart Attack Study.
During the calendar years 1975, 1978, 1981, and 1984, a community-wide study in the Worcester, Massachusetts, metropolitan area has examined time trends in the attack and case fatality rates of acute myocardial infarction (MI) as well as the occurrence of out-of-hospital coronary heart disease deaths. Between 1975 and 1981, there was a slight increase in the age-adjusted attack rates of acute MI; between 1981 and 1984, however, there was a dramatic decline in the incidence rates of acute MI. These temporal trends over the 10-year period examined resulted in an overall decrease in both the incidence rates of initial (255 per 100,000-1975; 186 per 100,000-1984) as well as recurrent (133 per 100,000-1975; 104 per 100,000-1984) acute MI in the 16 hospitals surveyed. The age-adjusted in-hospital case fatality rates of acute MI declined consistently over the periods studied, from 22.2% in 1975 to 20.3% in 1978, 17.8% in 1981, and to 15.1% in 1984, for an overall decline of 32% over the 10-year period studied. No significant differences, however, were seen in the long-term survival rates of patients discharged from the hospital after acute MI in either 1975, 1978, 1981, or 1984. A consistent decline was seen in the age-adjusted mortality rates (per 100,000) of out-of-hospital coronary heart disease between 1975 (265), 1978 (174), 1981 (170), and 1984 (148).(ABSTRACT TRUNCATED AT 250 WORDS)
Pulmonary artery catheters.
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Arrhythmias in the assessment of coronary artery reperfusion following thrombolytic therapy.
Arrhythmias are used as markers of coronary reperfusion after administration of thrombolytic agents. We studied the effects of coronary recanalization on the development of arrhythmias in patients receiving thrombolytic agents during the early hours of acute myocardial infarction. Acute cardiac catheterization, assessing perfusion of the infarction-related artery and identifying the arrhythmias, was performed within eight hours of onset of symptoms. Fifty-six of 67 patients (84 percent) studied had total occlusion of the infarction-related artery, 25 of whom had restoration of coronary flow during the 90 minutes after initiation of therapy; 31 had no evidence of reperfusion. Eleven patients had subtotal vessel occlusion that did not change appreciably during therapy, and 20 patients (30 percent) had transient arrhythmias. There were no significant differences in the frequency of arrhythmias: 36 percent of reperfused patients, 19 percent of nonreperfused, and 45 percent of subtotal occlusion patients. Only bradyarrhythmia was significantly related to the restoration of flow of the right coronary artery. Other rhythm disturbances, including accelerated idioventricular rhythm, did not correlate with a change in the perfusion status of the vessel. Bradycardia may be a useful marker for right coronary artery reperfusion. Arrhythmias in general are not specific for coronary reperfusion and should not be used as event markers.
Management of post-infarction angina.
Post-infarction angina includes a syndrome of ischemic chest pain occurring either at rest or during minimal activity 24 hours or more following an acute MI. It develops in approximately 10 to 15 per cent of patients and is particularly common in non Q-wave infarcts involving the anterior myocardial wall. Post-infarction angina may result from ischemia either within the infarct zone or at a distance and frequently portends a poor long term prognosis. Platelet aggregation, coronary vasospasm, and thrombus formation at the site of a ruptured atherosclerotic plaque are each involved in its pathogenesis. The initial treatment of post-infarction angina includes identification and correction of factors that increase myocardial demand including congestive heart failure and arrhythmias. beta-Adrenergic blockers, calcium channel blockers, and nitrate preparations constitute the first line of medical therapy. The role of heparin is controversial, yet it continues to be used in clinical practice. Although thrombolytic agents are currently being investigated, early experience suggests that they may accelerate clinical stabilization and allow time for elective revascularization when required. Antiplatelet therapy with aspirin has proven benefit in the long term management of unstable angina. Patients unresponsive to medical therapy should be considered for intra-aortic balloon pump placement and early coronary angiography. Revascularization with either coronary angioplasty or coronary artery bypass grafting may then be performed as dictated by the overall clinical status, available facilities, and coronary anatomy.
Peak creatine kinase as a measure of effectiveness of thrombolytic therapy in acute myocardial infarction.
As part of the National Heart, Lung, and Blood Institute multicenter Thrombolysis in Myocardial Infarction Trial, the time to peak plasma creatine kinase (CK) activity as a marker of reperfusion in 272 patients with validated acute myocardial infarction was analyzed. Patients were treated with either tissue-type plasminogen activator or streptokinase by intravenous administration. All patients underwent acute coronary angiography. The infarct-related artery was identified and thrombolytic therapy administered. Reperfusion at 90 minutes was documented by angiography. CK was determined before institution of therapy and every 4 hours thereafter for the first 24 hours. Patients were classified into 3 groups for comparative purposes: group 1--occlusion with no reperfusion (n = 119); group 2--occlusion with reperfusion (n = 98); and group 3--subtotal occlusion (n = 55). Early (within 4 hours after treatment) and late (more than 16 hours after treatment) peaking of CK differentiated patients with drug-induced perfusion from those without reperfusion. Although peak CK between 5 and 11 hours after drug treatment did suggest perfusion through the infarct-related artery, it did not differentiate between drug-induced and spontaneous reperfusion. Clinically, early peak CK is a useful noninvasive means of assessing coronary artery patency. However, in clinical trials assessing drug therapy, the use of peak CK may overestimate drug effectiveness by including patients with spontaneous reperfusion.
Outcome after cardiac arrest during acute myocardial infarction.
A community-wide study of acute myocardial infarction (AMI) was conducted in all 16 acute-care general hospitals in the Worcester, Massachusetts, metropolitan area during the years 1975, 1978, 1981 and 1984. The in-hospital and long-term prognoses of 667 patients with AMI complicated by cardiac arrest (CA) was compared with that of 2,596 AMI patients without CA. The incidence of CA complicating AMI was similar (21%) during each of the 4 study years. Among patients with AMI who had CA, 36% had CA within the first day of hospitalization and 48% within the first 2 days. The in-hospital case-fatality rate was much higher for AMI patients with CA (78%) than for those without CA (4%) (p less than 0.001). For patients discharged alive from the hospital, a trend toward a higher mortality rate was seen at 1 and 2 years after hospital discharge for patients with CA; however, long-term survival rates were not significantly different between AMI patients with and without CA. When time of occurrence of CA relative to in-hospital survival was examined, patients with early CA (within 1 day or within 2 days of hospital admission) had a significantly greater in-hospital survival (39% and 34%) than did those with late CA (after 1 day or after 2 days) (13% and 12%). Similarly, patients discharged from the hospital after early CA had a significantly better chance of long-term survival than patients discharged after late CA.
Therapeutic trends in the management of patients with acute myocardial infarction (1975-1984): the Worcester Heart Attack Study.
As part of an ongoing community-wide study of time trends in the incidence and case-fatality rates of patients hospitalized with acute myocardial infarction (MI) in all 16 Worcester, Massachusetts, metropolitan hospitals during the years 1975, 1978, 1981, and 1984, changes over time in the therapeutic management of 3263 patients with validated acute myocardial infarction were examined. Beta-blocker (21%, 1975; 52%, 1984) and nitrate (56%, 1975; 93%, 1984) therapy use increased dramatically over time. Use of antiplatelet agents was inconsistent over time, while use of digoxin remained stable, being used in approximately 40% of all patients over the four periods studied. Use of antiarrhythmic medications other than lidocaine decreased consistently over time (31%, 1975; 22%, 1984). Lidocaine use increased between 1975 (31%) and 1978 (52%) and then leveled off to being used in approximately 45% of hospitalized patients with acute MI in 1981 and 1984. A variety of demographic (e.g., age, sex, teaching hospital) and clinical characteristics (e.g., MI order, MI type, MI location, peak CPK findings, occurrence of acute clinical complications) were also associated with the use of these therapies for the combined study periods. The results of this population-based study suggest considerable changes over time in the therapeutic management of patients hospitalized with acute myocardial infarction and of numerous patient demographic and clinical factors associated with their use.
Non-Q wave myocardial infarction: recent changes in occurrence and prognosis--a community-wide perspective.
A community-wide study of patients hospitalized with validated acute myocardial infarction (MI) in all 16 hospitals in the Worcester metropolitan area, during the calendar years 1975, 1978, and 1981, is examining time trends in the incidence rates, in-hospital case fatality rates, and long-term survival rates of 2451 patients hospitalized with acute MI further classified into those with Q wave and those with non-Q wave MI. The age-adjusted hospital attack rates (per 100,000) of initial events of Q wave MI increased from 153 in 1975 to 197 in 1981 (p less than 0.05), while the attack rates of non-Q wave MI increased from 46 in 1975 to 89 in 1981 (p less than 0.001). Patients with non-Q wave MI were at significantly decreased risk of dying during hospitalization (12.0%) as compared to those with Q wave MI (25.2%), overall as well as for each of the three time periods studied (p less than 0.05). For patients discharged alive from the hospital, however, there were no significant differences in long-term survival rates according to MI type over an 8-year follow-up period. These results, obtained from a community-wide sample of patients with validated acute MI, indicate a significant change in the occurrence rates and/or recognition of non-Q wave MI, a significantly lower in-hospital case fatality rate for patients with non-Q wave MI, and comparable long-term prognosis for patients with Q wave and non-Q wave acute MI.