Stuart Zarich

Cardiac Outcome after Peripheral Vascular Surgery: Comparison of General and Regional Anesthesia

Background Despite evidence that regional anesthesia may be associated with fewer perioperative complications than general anesthesia, most studies that have compared cardiac outcome after general or regional anesthesia alone have not shown major differences. This study examines the impact of anesthetic choice on cardiac outcome in patients undergoing peripheral vascular surgery who have a high likelihood of associated coronary artery disease. Methods Four hundred twenty‐three patients, between 1988 and 1991, were randomly assigned to receive general (n = 138), epidural (n = 149), or spinal anesthesia (n = 136) for femoral to distal artery bypass surgery. All patients were monitored with radial artery and pulmonary artery catheters. Postoperatively, patients were in a monitored setting for 48–72 h and had daily electrocardiograms for 4–5 days and creatine phosphokinase/isoenzymes every 8 h x 3, then daily for 4 days. Cardiac outcomes recorded were myocardial infarction, angina, and congestive heart failure. Results Baseline clinical characteristics were not different between anesthetic groups. Overall, the patient population included 86% who were diabetic, 69% with hypertension, 36% with a history of a prior myocardial infarction, and 41% with a history of smoking. Cardiovascular morbidity and overall mortality were not significantly different between groups when analyzed by either intention to treat or type of anesthesia received. In the intention to treat analysis, incidences of cardiac event or death for general, spinal, and epidural groups were 16.7%, 21.3%, and 15.4%, respectively. The absolute risk difference observed between general and all regional anesthesia groups for cardiac event or death was ‐1.6% (95% confidence interval ‐9.2%, 6.1%) This reflected a nonsignificant trend for lower risk of postoperative events with general anesthesia. Conclusions The choice of anesthesia, when delivered as described, does not significantly influence cardiac morbidity and overall mortality in patients undergoing peripheral vascular surgery.

Diastolic abnormalities in young asymptomatic diabetic patients assessed by pulsed Doppler echocardiography

Indexes of left ventricular diastolic filling were measured by pulsed Doppler echocardiography in 21 insulin-dependent diabetic patients and 21 control subjects without clinical evidence of heart disease. No patient had chest pain or electrocardiographic changes during exercise testing. The mean age of patients was 32 years. All patients had a normal ejection fraction. Six (29%) of the 21 diabetic patients had evidence of diastolic dysfunction as assessed by the presence of at least two abnormal variables of mitral inflow velocity. The ratio of peak early to peak late (atrial) filling velocity was significantly decreased in diabetic compared with control subjects (1.24 +/- 0.21 versus 1.66 +/- 0.30, p. less than 0.001). Atrial filling velocity was significantly increased in diabetic patients (74.3 +/- 16.7 versus 60.3 +/- 12.2 cm/s, p less than 0.004), whereas early filling velocity was reduced by a nearly significant degree (88.8 +/- 12.6 versus 98.5 +/- 18.8 cm/s, p less than 0.057). The atrial contribution to stroke volume as assessed by area under the late diastolic filling envelope compared to total diastolic area was also significantly increased in diabetic compared with control subjects (35 versus 27%, p less than 0.001). Left ventricular diastolic filling abnormalities in diabetic patients did not correlate with duration of diabetes, retinopathy, nephropathy or peripheral neuropathy. These data suggest that approximately one-third of such patients have subclinical myocardial dysfunction unrelated to accelerated atherosclerosis. Doppler echocardiography may offer a reliable noninvasive means to assess diastolic function and to follow up diabetic patients serially for any deterioration in cardiac status before the appearance of clinical symptoms.

Left ventricular filling abnormalities in asymptomatic morbid obesity

Indexes of left ventricular (LV) diastolic filling were measured by pulse Doppler echocardiography in 16 asymptomatic morbidity obese patients presenting for bariatric surgery and were compared with an age- and sex-matched lean control population. No patient had concomitant disorders known to affect diastolic function. All patients had normal systolic function. LV wall thickness and internal dimension were measured in order to calculate LV mass. Fifty percent of morbidly obese patients had LV diastolic filling abnormalities as assessed by the presence of greater than or equal to 2 abnormal variables of mitral inflow velocity. The ratio of peak early to peak late (atrial) filling velocity was significantly decreased in obese compared with control patients (1.16 +/- 0.26 vs 1.66 +/- 0.30, p less than 0.001). The peak velocity of early LV diastolic filling was significantly reduced in obese patients (75 +/- 15 vs 98 +/- 19 cm/s, p less than 0.001). The atrial contribution to stroke velocity as assessed by the time-velocity integral of late compared with total LV diastolic filling was significantly increased in obese patients (36 +/- 7 vs 27 +/- 4%, p less than 0.001). Obese patients had significantly increased LV mass (214 +/- 45 vs 138 +/- 37 g, p less than 0.001), even when corrected for body surface area (95 +/- 16 vs 76 +/- 16 g/m2, p less than 0.002). However, increased LV mass did not correlate with indexes of abnormal diastolic filling in obese patients. These data suggest that abnormalities of diastolic function occur frequently in asymptomatic morbidly obese patients and may represent a subclinical form of cardiomyopathy in the obese patient.

Silent myocardial ischemia and infarction in diabetics with peripheral vascular disease: Assessment by dipyridamole thallium-201 scintigraphy

We investigated the incidence of silent myocardial ischemia and infarction as assessed by dipyridamole thallium scintigraphy in 30 diabetic patients with peripheral vascular disease and without clinical suspicion of coronary artery disease. Seventeen patients (57%) had thallium abnormalities, with reversible thallium defects compatible with ischemia in 14 patients (47%) and evidence of prior, clinically silent myocardial infarction in 11 patients (37%). Thallium abnormalities were most frequent in patients with concomitant hypertension and cigarette smoking (p = 0.001). These results suggest that unsuspected coronary artery disease is common in this particular group of patients with diabetes mellitus.

Acute Myocardial Infarction in Diabetes Mellitus Lessons Learned From ACE Inhibition

Diabetes mellitus affects ≈6% of the US population but is present in as many as 30% of patients hospitalized with acute coronary syndromes. It has been recognized for some time that diabetics experience a greater mortality during the acute phase of myocardial infarction (MI) and a higher morbidity in the postinfarction period (see recent reviews in References 1 and 21 2 ). Before the advent of coronary care as we know it today, mortality among diabetic patients in MI was reported to be as high as 40%3 and at least double the mortality rate in patients without diabetes. More extensive coronary artery disease, additional cardiovascular risk factors, and other end-organ disease were thought to be largely responsible for this major difference in outcome. Current treatment of acute MI derived from large clinical trials has dramatically improved survival in both nondiabetic and diabetic patients. However, despite these improvements, diabetes still doubles the case-fatality rate. In the GUSTO-1 angiography substudy report,4 this twofold increase in relative risk of 30-day mortality persisted even after adjustment for the factors cited above. What is this “diabetic factor”? It is in this context that new information on this topic must be evaluated. In the December 16, 1997, issue of Circulation , the GISSI-3 investigators compare the effect of early administration (within 24 hours of admission) of lisinopril in patients with and without diabetes mellitus in MI.5 Compared with placebo, lisinopril dramatically reduced both 6-week and 6-month mortality in diabetics versus nondiabetics (6 weeks, 30% versus 5% and 6 months, 20% and 0%, respectively). Furthermore, the incidence of drug-related adverse effects was similar between the two groups within the blood pressure and renal function parameters used in that study. This experience, along with the subgroup analyses of SAVE6 and TRACE,7 should …

Myocardial ischemia and weaning failure in patients with coronary artery disease: an update.

OBJECTIVE To determine the frequency and effects of weaning-related myocardial ischemia on weaning outcomes in patients with coronary artery disease. DESIGN Prospective cohort study. SETTING Medical and cardiac intensive care units of a 300-bed teaching community hospital. MEASUREMENTS AND MAIN RESULTS Three-lead ST segments, heart rate-systolic blood pressure products, and respiratory rate/tidal volume ratios were obtained for patients with coronary artery disease just before and during their initial trials of weaning from mechanical ventilation. ST segments were interpreted by a blinded cardiologist. Eighty-three patients with a mean age of 72.4 +/- 1.1 years (mean +/- SEM), a mean Acute Physiology and Chronic Health Evaluation II score of 16.4 +/- 0.8, and a mean duration of mechanical ventilation of 4.6 +/- 0.9 days were studied. Eight patients showed electrocardiographic evidence of ischemia during weaning, and seven of these patients failed to be liberated on their first day of weaning. The presence of ischemia significantly increased the risk of weaning failure (risk ratio, 2.1; 95% confidence interval, 1.4-3.1). The rate-pressure product for the group as a whole increased significantly during weaning, from 11.9 +/- 0.4 to 13.5 +/- 0.5 mm Hg x beats/min x 10(3) (p < .01). The increase in rate-pressure product tended to be greater in patients who became ischemic (12.8 +/- 0.9 to 17.3 +/- 2.0 mm Hg x beats/min x 10(3)) than in patients who were not ischemic during weaning (11.8 +/- 0.4 to 13.0 +/- 0.5 mm Hg x beats/min x 10(3); p = .05). The rate/volume ratio did not change significantly during weaning, but the rate/volume ratios after both 1 min (65.6 +/- 4.6 vs. 98.0 +/- 9.4 breaths/min/L; p < .05) and 30 mins (68.6 +/- 4.3 vs. 91.1 +/- 8.9 breaths/min/L; p < .05) of unassisted breathing were lower in successful than in unsuccessful patients. CONCLUSION Electrocardiographic evidence of myocardial ischemia occurs frequently and is associated with significantly increased risk of first-day weaning failure in patients with coronary artery disease.

Angioscopic Predictors of Early Adverse Outcome After Coronary Angioplasty in Patients With Unstable Angina and Non–Q-Wave Myocardial Infarction

BACKGROUND Clinical and angiographic criteria have a limited ability to predict adverse outcome in patients with unstable angina who are undergoing percutaneous transluminal coronary angioplasty (PTCA). We investigated whether the use of angioscopy can improve prediction of early adverse outcome after PTCA. METHODS AND RESULTS Angioscopic characterization of the culprit lesion was performed before PTCA in 32 patients with unstable angina and 10 with non-Q-wave infarction. Seven patients (17%) had an adverse outcome (myocardial infarction, repeat PTCA, or need for coronary artery bypass graft surgery) within 24 hours after PTCA. Six of 18 patients with a yellow culprit lesion had an adverse outcome compared with 1 of 24 in whom the culprit lesion was white (P = .03). Six of 20 patients with plaque disruption suffered an adverse outcome compared with 1 of 22 with nondisrupted plaques (P = .04). Six of 17 patients with intraluminal thrombus had an adverse outcome, whereas only 1 of 25 patients without thrombus suffered an adverse outcome (P = .01). Yellow color, disruption, and thrombus at the culprit lesion site were associated with an eightfold increase in risk of adverse outcome after PTCA. The prediction of PTCA outcome based on characteristics of the plaque that were identifiable by angioscopy was superior to that estimated by the use of angiographic variables. CONCLUSIONS In patients with unstable angina and non-Q-wave infarction, angioscopic features of disruption, yellow color, or thrombus at the culprit lesion site can identify patients at high risk of early adverse outcome after PTCA. Angioscopy was superior to angiography for prediction of PTCA outcome.

Effect of autonomic nervous system dysfunction on the circadian pattern of myocardial ischemia in diabetes mellitus

OBJECTIVES The aim of this study was to determine the prevalence and characteristics of ambulatory myocardial ischemia in patients with diabetes mellitus and to delineate the relation between the presence and severity of autonomic nervous system dysfunction and the incidence and time of onset of myocardial ischemia. BACKGROUND Conflicting data exist with regard to the circadian pattern of myocardial infarction and other cardiovascular events, such as ambulatory ischemia, in diabetes. METHODS We performed ambulatory electrocardiographic monitoring in 60 patients with diabetes and coronary artery disease. Autonomic nervous system testing was performed in a subgroup of 25 patients with myocardial ischemia after discontinuation of all antianginal medications. RESULTS Thirty-eight of 60 patients had evidence of ambulatory ischemia; 91% of all ischemic episodes were asymptomatic. The 25 patients with ambulatory ischemia who underwent autonomic nervous system testing had a peak incidence of ischemia between 6 AM and noon (46 of 133 ischemic episodes, p < 0.007), compared with the other three 6-h periods. Fifteen of the 25 patients had no or mild autonomic nervous system dysfunction and demonstrated a similar peak incidence of ischemia between 6 AM and noon (p = 0.0009). However, the 10 patients with moderate to severe autonomic nervous system dysfunction did not experience a morning peak of ischemia, and the number of ischemic episodes was distributed evenly throughout the day (p = 0.4). CONCLUSIONS Silent ischemia is highly prevalent among patients with diabetes and coronary artery disease. Time of onset of ischemia in diabetic patients follows a circadian distribution, with a peak incidence in the morning hours. However, patients with significant autonomic nervous system dysfunction did not demonstrate such a peak, suggesting that alterations in sympathovagal balance may have an effect on the circadian pattern of cardiovascular events.

Severity of coronary artery disease in young patients with insulin-dependent diabetes mellitus

Cardiovascular events remain a leading cause of morbidity and mortality in patients with juvenile-onset, insulin-dependent diabetes mellitus. To examine the extent and severity of the atherosclerotic lesions underlying this excess morbidity and mortality, clinical and angiographic findings were examined in 32 patients with insulin-dependent diabetes and in 31 nondiabetic patients, matched for age and symptoms, undergoing elective cardiac catheterization for evaluation of coronary artery disease. With respect to the individuals without diabetes, patients with insulin-dependent diabetes were significantly more likely to have severe narrowings, to have them in all three major coronary arteries, and to have them in distal segments. Severe narrowing of multiple vessels was significantly more common in men than in women and in individuals with hypercholesterolemia. We conclude that the high risk of cardiovascular events observed in young patients with insulin-dependent diabetes is secondary to advanced atherosclerotic lesions in coronary arteries. Involvement of distal segments of coronary arteries make these patients frequently unsuitable for bypass grafts.

Outcomes of critically ill patients who received cardiopulmonary resuscitation.

RATIONALE Studies examining survival outcomes after in-hospital cardiopulmonary arrest (CPA) among intensive care unit (ICU) patients requiring medications for hemodynamic support are limited. OBJECTIVES To examine outcomes of ICU patients who received cardiopulmonary resusitation. METHODS We identified 49,656 adult patients with a first CPA occurring in an ICU between January 1, 2000 and August 26, 2008 within the National Registry of Cardiopulmonary Resuscitation. Survival outcomes of patients requiring hemodynamic support immediately before CPA were compared with those of patients who did not receive hemodynamic support (pressors), using multivariable logistic regression analyses to adjust for differences in demographics and clinical characteristics. Pressor medications included epinephrine, norepinephrine, phenylephrine, dopamine, dobutamine, and vasopressin. MEASUREMENTS AND MAIN RESULTS The overall rate of survival to hospital discharge was 15.9%. Patients taking pressors before CPA were less likely to survive to discharge (9.3 vs. 21.2%; P < 0.0001). After multivariable adjustment, patients taking pressors before pulseless CPA were 55% less likely to survive to discharge (adjusted odds ratio [OR], 0.45; 95% confidence interval [CI], 0.42-0.48). Age equal to or greater than 65 years (adjusted OR, 0.77; 95% CI, 0.73-0.82), nonwhite race (adjusted OR, 0.58; 95% CI, 0.54-0.62), and mechanical ventilation (adjusted OR, 0.60; 95% CI, 0.56-0.63) were also variables that could be identified before CPA that were independently associated with lower survival. More than half of survivors were discharged to rehabilitation or extended care facilities. Only 3.9% of patients who had CPA despite pressors were discharged home from the hospital, as compared with 8.5% of patients with a CPA and not taking pressors (adjusted OR, 0.53; 95% CI, 0.49-0.59). CONCLUSIONS Although overall survival of ICU patients was 15.9%, patients requiring pressors and who experienced a CPA in an ICU were half as likely to survive to discharge and to be discharged home than patients not taking pressors. This study provides robust estimates of CPR outcomes of critically ill patients, and may assist clinicians to inform consent for this procedure.