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Biomedical subjects

M C Gerson

Publications and source records attributed to M C Gerson.

At least 37 records · Page 2Linked to original sources

Prediction of cardiac and pulmonary complications related to elective abdominal and noncardiac thoracic surgery in geriatric patients.

PURPOSE: Major cardiac and pulmonary complications associated with abdominal and noncardiac thoracic surgery are a common cause of mortality and serious morbidity in elderly patients. We postulated that a simple, inexpensive bicycle exercise test could provide objective documentation of cardiopulmonary reserve and, therefore, predict perioperative pulmonary as well as cardiac complications. PATIENTS AND METHODS: Prior to elective surgery, 177 patients aged 65 years or older had assessment of the clinical history, results of physical examination, electrocardiogram, chest radiograph, blood chemistries, pulmonary function test findings, supine exercise test results, Dripps classification, and Goldman cardiac risk factors. Observations in patients with and without major perioperative cardiac and/or pulmonary complications were compared using univariate analysis followed by a multivariate logistic regression procedure. RESULTS: Major perioperative complications were pulmonary in 24 patients, cardiac in 25 patients, and either cardiac or pulmonary in 39 patients. By multivariate analysis, inability to perform two minutes of supine bicycle exercise raising the heart rate above 99 beats/minute was the best predictor of perioperative pulmonary, cardiac, and combined cardiopulmonary complication (p less than 0.0005). Among 108 patients who were able to achieve these exercise criteria, cardiac or pulmonary complications occurred in 10 patients (9.3%), with one death (0.9%). Among 69 patients unable to exercise satisfactorily, cardiac or pulmonary complications occurred in 29 patients (42%), with five total deaths (7.2%). CONCLUSION: Objective measurement of exercise capacity by supine bicycle ergometry appears to be of clinical value for preoperative risk stratification for both pulmonary and cardiac complications prior to major elective abdominal or noncardiac thoracic surgery in elderly patients.

Abdomen↗

Differentiation of constrictive pericarditis and restrictive cardiomyopathy by radionuclide ventriculography.

Patterns of left ventricular diastolic filling in five patients with unoperated constrictive pericarditis, the same five patients following pericardiectomy, five patients with restrictive cardiomyopathy, and 14 healthy control subjects were studied by radionuclide ventriculography. Patients with constrictive pericarditis had more rapid peak left ventricular filling rates (mean 5.62, range 4.23 to 7.32 end-diastolic volumes [EDV] per second) compared to control subjects 3.44, range 2.62 to 4.45 EDV/sec, p less than 0.05). Heart rate-corrected first one-third and first one-half diastolic filling fractions were greater in patients with preoperative constrictive pericarditis compared to members of the restrictive cardiomyopathy and control groups p less than 0.05). Following pericardiectomy, patients with constrictive pericarditis had significant decreases in peak filling rate and corrected filling fractions, and all diastolic filling measurements were indistinguishable from those of control subjects. These noninvasively obtained data indicate that patients with preoperative constrictive pericarditis have an increased rate of left ventricular early diastolic filling compared to patients with restrictive cardiomyopathy and control subjects, and that these findings return to normal following surgical removal of the pericardium.

Adult↗

Prediction of coronary artery disease in a population of insulin-requiring diabetic patients: results of an 8-year follow-up study.

To identify predictors of clinical coronary artery disease, 110 insulin-requiring diabetic patients with no symptoms suggestive of cardiac disease and with a normal resting ECG underwent metabolic and noninvasive cardiovascular screening including a history and physical examination, exercise ECG, M-mode echocardiography, and chemical laboratory testing. During a median follow-up interval of 100 months, 14 of these patients had clinical evidence of coronary artery disease consisting of acute myocardial infarction, sudden cardiac death, or anginal chest pain with angiographic documentation of occlusive coronary artery disease. Baseline variables that were univariately predictive of subsequent clinical coronary disease included age, peak treadmill heart rate, and retinal neovascularization. According to multivariate analysis the peak treadmill heart rate was the single most important predictor of subsequent development of clinical coronary disease. A treadmill ECG result that was either abnormal or inconclusive because of failure to achieve 90% of predicted maximal heart rate identified each patient in whom clinical coronary artery disease developed within 50 months after entry testing. Thus the entry treadmill ECG provided prognostic information not available from the history and physical examination results, but little further prognostic information was provided after the first 50 months of follow-up, suggesting the need for serial testing.

Adolescent↗

Simulation of abnormal pulmonary thallium-201 activity following mastectomy.

Increased uptake of activity in one lung field was found on postexercise Tl-201 images in a woman who had undergone a previous mastectomy on that side. This was probably related to a partial loss of normal tissue attenuation following surgery, resulting in a simulation of abnormal pulmonary activity.

Female↗

Cardiac prognosis in noncardiac geriatric surgery.

Predictors of perioperative complications, including cardiac death, ventricular tachycardia or fibrillation, and heart failure or myocardial infarction, were assessed in an initial study of 100 patients aged 65 years or older scheduled for elective abdominal or noncardiac thoracic surgery. Preoperative history, results of physical examination, chest roentgenogram, electrocardiogram, laboratory data, Dripps (American Society of Anesthesiologists) class, and Goldman cardiac risk index were compared with rest and exercise radionuclide ventriculograms. Thirteen patients had perioperative cardiac complications, and 6 died. Multivariate analysis showed that an inability to do 2 minutes of bicycle exercise in the supine position to raise the heart rate above 99 beats/min (sensitivity 85%, specificity 64%) gave predictive information not available from clinical or radionuclide data. On prospective testing involving 55 additional geriatric patients, inability to exercise was the only independent predictor of perioperative complications (p less than 0.05). Data from rest and exercise radionuclide ventriculography added little information for predicting perioperative cardiac risk.

Abdomen↗

Myocardial scintigraphy with 99mTc-tris-DMPE in man.

Cardiac scintigraphy was performed in six patients with a documented previous myocardial infarction, in one patient with mitral regurgitation, and in four healthy volunteers following administration of 99mTc-tris-DMPE. An intense early blood pool phase permitted gated blood pool scintigraphy and left ventricular ejection fraction calculation. A myocardial phase 12-14 h later permitted myocardial perfusion imaging. The rest myocardial perfusion image quality with 99mTc-tris-DMPE appeared to be superior to the resting image quality obtained with 99mTc-dichloro-DMPE but was inferior to the resting image quality obtained with 201Tl.

Aged↗

Simulation of acute myopericarditis by constrictive pericardial disease with endomyocardial fibrosis due to methysergide therapy.

Methysergide ( Sansert ) has been associated with numerous fibrotic disorders. In particular, multiple cardiac lesions have been described in cases where methysergide was thought to have played a causative role. A patient is described who presented with cardiac findings suggestive of acute myopericarditis . An inflammatory myocarditis was subsequently excluded by endomyocardial biopsy. Hemodynamic findings suggested the presence of constrictive pericarditis or restrictive cardiomyopathy, or both. Radiographic evidence of constrictive pericarditis and biopsy evidence of endocardial fibrosis were documented in this patient with a long history of interrupted methysergide therapy.

Acute Disease↗

Effects of dynamic and isometric exercise on the radionuclide-determined regurgitant fraction in aortic insufficiency.

Twenty-five patients with aortic insufficiency and eight asymptomatic control subjects underwent radionuclide ventriculography at rest and during dynamic and isometric exercise to clarify the mechanisms for preservation of exercise capacity in aortic insufficiency. Regardless of symptomatic state or severity of regurgitation, patients with aortic insufficiency had no significant increase in left ventricular ejection fraction or relative left ventricular end-diastolic volume during dynamic or isometric exercise. The radionuclide stroke count ratio (ratio of left ventricular to right ventricular stroke counts) progressively decreased in patients with aortic insufficiency from 2.98 +/- 1.14 (mean +/- 1 standard deviation) at a mean heart rate at rest of 69.6 beats/min to 2.48 +/- 0.59 (p = not significant [NS]) at a mean submaximal bicycle exercise heart rate of 129 beats/min and to 1.97 +/- 0.57 (p less than 0.005) at a mean maximal bicycle exercise heart rate of 145 beats/min. The decrease in stroke count ratio with bicycle exercise was significantly related to the severity of valvular regurgitation at rest (p less than 0.005). Although achieving lower bicycle exercise heart rates and comparable diastolic blood pressures, symptomatic patients had a lower mean stroke count ratio compared with asymptomatic patients with aortic insufficiency, suggesting that an elevation left ventricular diastolic pressure significantly decreased the regurgitant fraction in symptomatic patients during bicycle exercise. In patients with aortic insufficiency, the mean heart rate (92 beats/min) was significantly lower with isometric exercise than during the submaximal stage of bicycle exercise (129 beats/min). However, diastolic blood pressures, left ventricular diastolic counts and ejection fractions were comparable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Myocardial perfusion imaging with 99mTc-DMPE in man.

Technetium-99m DMPE (99mTc-DMPE) is a newly synthesized myocardial perfusion imaging agent that shows intense myocardial accumulation in the dog. In the present study, dosimetry and potential clinical usefulness of this agent were assessed in four human subjects. Absorbed radiation doses were low, with the highest doses consisting of 200 mrad/mCi (54 microGy/MBq) to the gallbladder and 160 mrad/mCi (43 microGy/MBq) to the liver. No evidence of clinical toxicity was found. Technetium-99m DMPE did image the myocardium, but the ratio of target to nontarget activity was less favorable than that observed in the dog. Intense hepatic 99mTc-DMPE activity interfered with clinical imaging of the cardiac apex in two of the four subjects. We conclude that the prototype radiopharmaceutical, 99mTc-DMPE, is capable of myocardial perfusion imaging in man but the planar myocardial images produced are of inferior quality compared with 201Tl myocardial images. Further work is justified to develop related compounds to overcome the clinical limitations described.

Adult↗

Evidence of left ventricular aneurysm by thallium-201 myocardial scintigraphy.

TI-201 myocardial scintigrams from 100 patients were reviewed for evidence of left ventricular aneurysms without prior knowledge of the clinical or angiographic data. Scintigraphic evidence of left ventricular aneurysms was considered present when TI-201 myocardial activity extended outward from the expected left ventricular contour in a region adjacent to an area of resting scintigraphic hypoperfusion. Scintigraphic findings suggestive of left ventricular aneurysm were detected in four patients, of whom three had angiographic evidence of left ventricular aneurysm. In the fourth patient, a dilated, akinetic left ventricular apex was present but an angiographic diagnosis of left ventricular aneurysm was not made. In three additional patients with angiographic evidence of left ventricular aneurysm, scintigraphic criteria for left ventricular aneurysm were absent. Although ungated TI-201 myocardial scintigraphy is an insensitive technique for the detection of left ventricular aneurysm, a characteristic scintigraphic pattern should suggest that a left ventricular aneurysm is present.

Female↗