Echocardiography for assessing cardiac risk in patients having noncardiac surgery. Study of Perioperative Ischemia Research Group.

Background: Cardiac complications after noncardiac surgery are a serious cause of illness and death. Echocardiography is being used before noncardiac surgery to assess risk for cardiac complications, but its role remains undefined.

Objective: To examine the prognostic value and operating characteristics of transthoracic echocardiography for assessing cardiac risk before noncardiac surgery.

Transthoracic and transesophageal echocardiography pre and post percutaneous mitral catheter balloon valvulotomy.

Catheter balloon valvulotomy (CBV) is useful in the relief of rheumatic mitral stenosis. Morphologic scoring of the mitral valve by transthoracic echocardiography is predictive of success with CBV. Horizontal plane transesophageal echocardiography can obtain high quality images of the mitral valve and left atrium, but its value with routine use in the pre and post CBV setting is unknown.

Scintigraphic and electrocardiographic evidence of silent coronary artery disease in asymptomatic hypertension: a case-control study.

Objectives: This study was conducted to determine the incidence of physiologically significant coronary artery disease in a group of asymptomatic high risk men with essential hypertension and to assess the validity of noninvasive tests in a subset of these patients undergoing coronary arteriography.

Methods: Two hundred twenty-six asymptomatic men (mean age 61 +/- 8 years) with essential hypertension and no clinical evidence of coronary artery disease but with at least one additional coronary risk factor were studied prospectively. Fifty age- and risk factor-matched normotensive subjects were evaluated as a control group.

Ventricular arrhythmias in patients undergoing noncardiac surgery. The Study of Perioperative Ischemia Research Group.

Objective: To determine the incidence, clinical predictors and prognostic importance of perioperative ventricular arrhythmias.

Design: Prospective cohort study (Study of Perioperative Ischemia).

Setting: University-affiliated Department of Veterans Affairs Medical Center, San Francisco, Calif.

Monitoring for myocardial ischemia during noncardiac surgery. A technology assessment of transesophageal echocardiography and 12-lead electrocardiography. The Study of Perioperative Ischemia Research Group.

Objective: Transesophageal echocardiography (TEE) and 12-lead electrocardiography (ECG) are sophisticated techniques that are increasingly being used to monitor for myocardial ischemia during noncardiac surgery. We examined whether the routine use of these techniques has incremental clinical value in identifying patients at high risk for perioperative ischemic outcomes when compared with preoperative clinical data and intraoperative monitoring using continuous two-lead bipolar ECG.

Design: Cohort study.

Predictors of postoperative myocardial ischemia in patients undergoing noncardiac surgery. The Study of Perioperative Ischemia Research Group.

Objective: To identify predictors of postoperative myocardial ischemia in patients scheduled to undergo major noncardiac surgery.

Design: Historical, clinical, laboratory, and physiological data were obtained prospectively before and during surgery to identify potential univariate predictors of postoperative myocardial ischemia, which then were entered into multivariate logistic models. Continuous two-lead electrocardiograms before, during, and after surgery were used to identify episodes of myocardial ischemia.

Diagnostic accuracy of exercise thallium-201 scintigraphy in men with asymptomatic essential hypertension.

Coronary artery disease is responsible for much of the morbidity and mortality in patients with essential hypertension, and these complications have proven to be relatively resistant to antihypertensive therapy. However, the diagnosis of coronary disease in the hypertensive population has been considered problematic. In the present study, 30 asymptomatic patients with mild to moderate hypertension with positive exercise electrocardiograms (ECG) or stress thallium-201 scintigrams underwent coronary angiography to determine the accuracy of these tests for coronary artery disease.

Hibernating myocardium: a historical perspective.

Hibernating myocardium refers to the presence of persistent myocardial and left ventricular dysfunction at rest, associated with conditions of severely reduced coronary blood flow. This left ventricular dysfunction probably represents an adaptive mechanism preventing irreversible myocardial cell damage, since myocardial and left ventricular dysfunction in hibernating myocardium improve following the restoration of coronary blood flow. This review examines the evolution of the concept of hibernation from a clinical observation of the potential underlying mechanisms recently proposed.

What is the role of silent coronary artery disease and left ventricular hypertrophy in the genesis of ventricular arrhythmias in men with essential hypertension?

Ventricular arrhythmias are not uncommon in patients with hypertension, are often attributed to left ventricular hypertrophy and are thought to be associated with an increased risk of sudden death. However, underlying silent coronary artery disease, another potential cause of ventricular arrhythmias, is often present in the same patient group. Therefore, the prevalence of ventricular arrhythmias was prospectively examined in 183 consecutive asymptomatic men with hypertension with neither clinical nor electrocardiographic (ECG) evidence of coronary artery disease in whom technically adequate echocardiograms could be obtained.

Measurement of left ventricular contractility using transesophageal echocardiography in patients undergoing coronary artery bypass grafting. The Study of Perioperative Ischemia (SPI) Research Group.

Optimal assessment of left ventricular function requires the use of load-independent indices of myocardial contractility, which often are difficult to obtain in patients undergoing coronary artery bypass graft (CABG) surgery. We have investigated whether the relation between left ventricular end-systolic stress (ESS) (derived from high-fidelity intraventricular pressure measurements and transesophageal-derived wall thickness) and end-systolic area (ESA) (derived from transesophageal echocardiography [TEE]) could provide a load-independent index of left ventricular function. We studied seven men undergoing coronary revascularization.

Dipyridamole thallium-201 scintigraphy as a preoperative screening test. A reexamination of its predictive potential. Study of Perioperative Ischemia Research Group.

Background: We examined the value of dipyridamole thallium-201 (201Tl) scintigraphy as a preoperative screening test for perioperative myocardial ischemia and infarction.

Methods And Results: We prospectively studied 60 patients undergoing elective vascular surgery. We performed 201Tl scintigraphy preoperatively and blinded all treating physicians to the results.

Perioperative myocardial ischemia in patients undergoing noncardiac surgery--II: Incidence and severity during the 1st week after surgery. The Study of Perioperative Ischemia (SPI) Research Group.

Because of the importance of postoperative myocardial ischemia and because substantial physiologic changes can occur for prolonged periods postoperatively, the incidence, severity and temporal course of myocardial ischemia were studied in 100 high risk patients during the 1st week after major noncardiac surgery. Electrocardiographic (ECG) changes consistent with ischemia were continuously monitored using ambulatory solid state ECG in the 100 patients with or at risk for coronary artery disease. Ischemic episodes were defined as reversible ST segment depression greater than or equal to 1 mm or elevation greater than or equal to 2 mm above the baseline value, with the baseline adjusted for respiratory and positional variation and temporal drift.

Perioperative myocardial ischemia in patients undergoing noncardiac surgery--I: Incidence and severity during the 4 day perioperative period. The Study of Perioperative Ischemia (SPI) Research Group.

To determine the incidence and characteristics of perioperative myocardial ischemia, the electrocardiographic (ECG) changes consistent with ischemia during the 4 day perioperative period were documented and characterized in 100 patients with or at risk for coronary artery disease undergoing noncardiac surgery. Using continuous two channel ECG monitoring (leads CC5 and CM5), the frequency and severity of ECG ischemic episodes defined by ST segment depression greater than or equal to 1 mm or elevation greater than or equal to 2 mm during the preoperative (up to 2 days), intraoperative and early postoperative (first 2 days) periods were compared. Preoperatively, 28 patients (28%) exhibited 105 episodes of ischemia; intraoperatively, 27 patients exhibited 39 episodes and postoperatively, 42 patients exhibited 187 episodes.

Influence of therapy on silent ischemia and ventricular arrhythmias in hypertensive patients.

To assess whether therapy with hydrochlorothiazide (HCTZ) or the calcium antagonist nitrendipine influences silent ischemia or arrhythmias, we studied 10 asymptomatic hypertensive male patients with positive Tl-201 scintigraphy in a double-blind, crossover protocol. Blood pressure (BP) and 48-h Holter monitoring were obtained after 2 weeks of placebo and 8 weeks each of HCTZ and nitrendipine therapy. Ischemia was defined as greater than 1 mm ST-segment depression lasting greater than 1 min and was quantified by the number of episodes, duration, and area under the curve (AUC).

Association of perioperative myocardial ischemia with cardiac morbidity and mortality in men undergoing noncardiac surgery. The Study of Perioperative Ischemia Research Group.

Background: Adverse cardiac events are a major cause of morbidity and mortality after noncardiac surgery. It is necessary to determine the predictors of these outcomes in order to focus efforts on prevention and treatment. Patients undergoing noncardiac surgery sometimes have postoperative cardiac events.

The "natural history" of segmental wall motion abnormalities in patients undergoing noncardiac surgery. S.P.I. Research Group.

Intraoperative segmental wall motion abnormalities (SWMA) detected by transesophageal echocardiography (TEE) are sensitive, but not always specific, markers of myocardial ischemia. To determine their incidence, characteristics, and relation to postoperative cardiac morbidity, we continuously recorded the left ventricular short-axis view and 12-lead ECG in 156 high-risk patients undergoing non-cardiac surgery. Monitoring was clinically blinded.

Correlates of diastolic filling abnormalities in hypertension: a Doppler echocardiographic study.

Hypertension and aging are both associated with changes of left ventricular (LV) diastolic filling and increased LV mass. To determine whether diastolic filling abnormalities are present in hypertension independent of aging and significant hypertrophy, we studied 19 hypertensive patients following a period of 4 weeks when they were not receiving therapy and 18 normotensive subjects matched for sex, age, and LV mass. All subjects had normal systolic function and ejection fraction as assessed by radionuclide angiography.

Left ventricular hypertrophy reversal with labetalol and propranolol: a prospective randomized, double-blind study.

Hypertensive patients with left ventricular hypertrophy (LVH) have increased cardiovascular morbidity and mortality. Experimental studies indicate the importance of both the alpha and beta components of the adrenergic nervous system in the development and reversal of LVH. Therefore labetalol (L), a combined alpha and beta blocker, and propranolol (P), a nonselective beta blocker, were evaluated in a randomized, double-blind study of 35 hypertensive patients with echocardiographic evidence of LVH.

Prognostic importance of postbypass regional wall-motion abnormalities in patients undergoing coronary artery bypass graft surgery. SPI Research Group.

Regional wall motion abnormalities (RWMA) detected by intraoperative transesophageal echocardiography (TEE) are thought to be sensitive markers of myocardial ischemia. To assess the prognostic significance of RWMA as compared with other less costly technologies such as electrocardiography (ECG) and hemodynamic measurements [blood pressure (BP) and pulmonary artery (PA) pressure], 50 patients were prospectively studied who were undergoing elective coronary artery bypass graft (CABG) surgery using continuous TEE, ECG (Holter), and hemodynamic measurements during the prebypass, postbypass, and early postoperative intensive care unit (ICU) periods (first 4 h). Echocardiographic and ECG evidence of ischemia was characterized during each of these three periods and related to adverse clinical outcomes (postoperative myocardial infarction, ventricular failure, and cardiac death).

Usefulness of thallium-201 scintigraphy in predicting the development of angina pectoris in hypertensive patients with left ventricular hypertrophy.

Hypertension and left ventricular (LV) hypertrophy are independent risk factors for the development of coronary artery disease. To determine whether patients at higher risk for coronary artery disease can be identified, 40 asymptomatic hypertensive men with LV hypertrophy were prospectively studied using exercise thallium-201 scintigraphy and exercise radionuclide angiography. Endpoints indicative of coronary artery disease were defined as the subsequent development of typical angina pectoris, which occurred in 8 patients during a median follow-up of 38 months, or myocardial infarction, which did not occur.

Impaired left ventricular functional reserve in hypertensive patients with left ventricular hypertrophy.

To determine whether patients with hypertension and especially those with left ventricular hypertrophy have subtle changes in cardiac function, we measured the increase in left ventricular ejection fraction and in systolic blood pressure to end-systolic volume index ratio with exercise in 40 hypertensive patients and 16 age-matched normotensive volunteers. Twenty-two hypertensive patients without hypertrophy had normal end-systolic wall stress at rest and exercise responses. In contrast, the 18 patients with echocardiographic criteria for left ventricular hypertrophy demonstrated a significant increase in end-systolic wall stress at rest compared with normal subjects (69 +/- 16 vs.

Coronary morbidity and mortality, pre-existing silent coronary artery disease, and mild hypertension.

Experimental findings in animals and epidemiologic studies in humans provide strong evidence that hypertension promotes the onset and progression of atherosclerosis. However, effective antihypertensive therapy has not consistently reduced the incidence of cardiac events in the major trials of treatment for mild hypertension. In reviewing these trials and the recent data on the pathophysiologic interrelationships among hypertension, atherosclerosis, and myocardial ischemia, two factors stand out: First, the power of these trials to produce a positive result was limited because of their size, entry criteria, duration, and other considerations; second, autopsy and epidemiologic data suggest that some patients in these trials probably had advanced coronary artery disease at the time of entry.