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Biomedical subjects

R M Abel

Publications and source records attributed to R M Abel.

At least 37 records · Page 2Linked to original sources
PubMed1983

Should nutritional status be assessed routinely prior to cardiac operation?

One hundred consecutive adult patients undergoing cardiac operations at a single institution were evaluated preoperatively with regard to their nutritional status. Anthropometric, biochemical, and immunologic characteristics were evaluated in addition to cardiac biopsy specimens to determine right atrial glycogen concentration. Although some positive anthropometric, biochemical, and cell-mediated immunity characteristics were observed to have "statistically significant" correlations with morbidity and mortality for the group as a whole, nearly all of the values remained near or at normal limits. Lighter weight men with a smaller arm muscle circumference and lower concentration of total body fat had more complications than their heavier counterparts. Serum transferrin and cell-mediated immunity also formed weakly positive statistical correlations. Anthropometric correlations in women were of no value. Myocardial glycogen concentrations did not correlate with postoperative morbidity and mortality. Because nearly all of the patients had arteriosclerotic heart disease, the series as a whole may have been skewed toward a group with values too close to normal to differentiate them adequately. It is concluded that routine nutritional assessment is of no value in guiding nutritional management for individual patients, although when patients are analyzed as a group, interesting epidemiologic observations can be made.

Adult↗
PubMed1981

Delayed sternal closure following open-heart operation.

Between June, 1976, and December, 1980, 29 patients underwent delayed sternal closure at the Newark Beth Israel Medical Center. The indications were enlarged heart with tamponade when the mediastinum was closed, poor lung compliance, hemodynamic instability due to intractable arrhythmias or coagulopathy, and presence of a mediastinal assist device. Following an open-heart procedure, the retrosternal space may no longer accommodate the heart and approximation of the sternum will produce hypotension and elevation of right and left end-diastolic pressures. In such instances, only the skin is closed and between one to four days later, the wound is closed in a routine manner. There are several advantages of the procedure: hemodynamic stability; quick access to the heart for massage or evacuation of clots; and possibility of removing an intraaortic balloon in the ascending aorta without leaving a large Dacron tube. Of the 29 patients treated, 19 were long-term survivors and only 1 patient had a minor superficial wound infection. Although it is not recommended that this procedure be utilized routinely or indiscriminately, its judicious use will add flexibility in the management of selected and difficult cases.

Adult↗
PubMed1980

Advantages of hypothermic potassium cardioplegia and superiority of continuous versus intermittent aortic cross-clamping.

The relative effectivenss of hypothermic potassium (K) cardioplegia in conjunction with either continuous or intermittent aortic cross-clamping was evaluated in 20 mongrel dogs. Isovolumetric left ventricular (LV) contractions and myocardial biopsies were obtained before and after a total of 90 minutes of aortic cross-clamping. The dogs were randomly divided into four groups of five dogs each as follows: Group I, continuous 90 minute cross-clamping and multidose K at 4 degrees C (40 mEq/L); Group II, intermittent cross-clamping consisting of six 15 minute periods of cross-clamping separated by 5 minute reperfusion periods and K cardioplegia at 4 degrees C given at the start of each cross-clamping period; Group III, continuous 90 minute cross-clamping and multidose buffered saline at 4 degrees C; Group IV, intermittent cross-clamping, consisting of six 15 minute periods of cross-clamping separated by 5 minute reperfusion periods and buffered saline at 4 degrees C given at the initiation of each cross-clamp period. Group I dogs had the best myocardial performance, with no difference between control values of peak LV pressure and dP/dtmax and those recordings obtained 60 minutes after release of the aortic cross-clamp. Significant depression of LV function was noted in all other groups. Examination of force-velocity and length-tension relationships confirmed better myocardial performance in Groups I and II (multidose K at 4 degrees C) than in Groups III and IV (buffered saline at 4 degrees C). Groups I and III (continuous cross-clamping) had no de-rease in diastolic LV compliance after cross-clamping, whereas compliance was decreased in both Groups II and IV (intermittent cross-clamping) at higher preloads (p less than 0.05 and p less than 0.025, respectively). The wet weight/dry weight myocardial ratios were lower in Groups I and III (continuous cross-clamping) than in Groups II and IV (intermittent cross-clamping). Although creatine phosphate (CP) concentrations were rapidly restored by reperfusion in all groups, adenosine triphosphate (ATP) and glycogen myocardial stores were better preserved at the end of cross-clamping in Groups I and II (multidose K at 4 degrees C). Although LV diastolic compliance was decreased and myocardial water content was increased in Groups II and IV (intermittent cross-clamping), no differences in the minimal extent of subendocardial hemorrhage, edema, and contraction-band necrosis were observed among any of the groups examined electron microscopically. The present study identifies continuous aortic cross-clamping with multidose K at 4 degrees C as a superior method of myocardial protection.

Animals↗
PubMed1980

Limb ischemia during intra-aortic balloon pumping: indication for femorofemoral crossover graft.

Catheter insertion for intra-aortic balloon pumping (IABP) was successful in 91% of 332 candidates. Fifty-three patients (16.5%) had significant catheter-associated vascular complications, of which lower extremity ischemia with threatened limb loss was the most prevalent (70%). Thirty-six of these patients required an angioplastic repair or vascular grafting. Of the 36, 19 patients with ischemia who needed continued balloon support received femorofemoral (F-F) grafts to restore and maintain adequate limb perfusion. Wound infection occurred in six of the patients but there was no limb loss. F-F grafting is a simple procedure that requires little time and allows one to maintain IABP for prolonged periods without concern for critical obstruction to limb perfusion.

Adult↗
PubMed1979

Adverse hemodynamic and ultrastructural changes in dog hearts subjected to protein-calorie malnutrition.

In the absence of thiamine deficiency, the specific effects of protein-calorie malnutrition on left ventricular (L.V.) function are unknown. Mature beagle dogs of both sexes were subjected to a hypocaloric, nitrogen-poor diet which resulted in a weight loss of approximately 40% after seven weeks. Following preparation of this nutritional model, myocardial contractility was assessed acutely by obtaining isovolumetric L.V. contractions on cardiopulmonary bypass at constant heart rate, mean aortic pressure, and at a wide range of end-diastolic volumes. These changes were compared to a matched group of animals which were normally fed. There were consistent decreases in L.V. compliance in malnourished animals compared with normals; indices of ventricular contractility per se (L.V. dp/dt, force-velocity relations, peak developed L.V. pressure) were also diminished in the experimental animals. Myocardial concentration of glycogen was diminished in malnourished compared to control animals. Light and electron microscopic examination confirmed the presence of myofibrillar atrophy in the presence of interstitial edema. These results suggest that protein-calorie malnutrition seriously interferes with normal L.V. function in the experimental animal by reducing compliance as a result of "starvation edema," and by reducing myocardial contractility associated with atrophy of the myofibers.

Animal Nutritional Physiological Phenomena↗
PubMed1979

Perioperative myocardial infarction associated with coronary artery bypass graft surgery: improved sensitivity in the diagnosis within 6 hours after operation with 99mTc-glucoheptonate myocardial imaging and myocardial-specific isoenzymes.

The present study was performed to evaluate scintigraphic imaging with technetium 99m-labeled glucoheptonate and serum enzyme levels of creatine phosphokinase isoenzyme (MB-CPK) in the early diagnosis of perioperative acute myocardial infarction associated with saphenous vein bypass graft operations. Myocardial imaging was done in 27 patients (50% of whom were considered high-risk) before operation and again 5 hours after operation. Four of these patients (15%) had both electrocardiographic and serum MB-CPK evidence of acute myocardial infarction, and all 4 had developed positive postoperative scintigrams. Four other patients had only elevated serum MB-CPK, and scintigrams became positive after operation in 3 of them. In addition, serum MB-CPK 6 hours after operation was 83 +/- 21 mIU/ml (mean +/- standard error of the mean) in patients with positive postoperative scans compared with 24 +/- 5 mIU/ml in those patients with negative postoperative scintigrams (p less than 0.001). Myocardial imaging with 99mTc-glucoheptonate in the perioperative period is rapid, safe, and atraumatic. Furthermore, our results suggest that it is a sensitive method for the early diagnosis of perioperative acute myocardial infarction, and, when imaging is combined with serum MB-CPK isoenzyme analysis, the reliability of the diagnosis of acute myocardial infarction is enhanced even further. Only 1 of the patients who showed perioperative myocardial damage had acute hemodynamic compromise or obvious impairment of recovery in the immediate postoperative period, and the 30-day mortality of the total group was 4% (1 of 27).

Acute Disease↗
PubMed1978

Role of delayed intraaortic balloon pumping in treatment of experimental myocardial infarction.

Intraaortic balloon pumping improves coronary blood flow characteristics while simultaneously reducing myocardial oxygen demands by reducing aortic systolic pressure. Clinical application of intraaortic balloon pumping has largely been in the "high risk" patient (cardiogenic shock, postinfarction angina, left main coronary artery disease and unstable angina) for support during diagnostic studies or cardiac surgery, or both. In addition, there is some evidence that balloon pumping immediately after coronary occlusion reduces the size of experimentally induced myocardial infarcts. In this study, myocardial infarcts were produced by ligation of the left anterior descending coronary artery in 12 dogs, 6 of which were treated with balloon counterpulsation beginning 3 hours after coronary occlusion. All dogs were killed 8 hours after coronary ligation. Intraaortic balloon pumping resulted in the expected hemodynamic changes (decreased aortic systolic pressure, left ventricular end-diastolic pressure and heart rate and increased aortic peak diastolic pressure). In addition, there was a significant reduction in infarct size in the group with balloon pumping as determined with epicardial S-T segment mapping, myocardial imaging with technetium-99m-glucoheptonate and histochemical staining with nitroblue tetrazolium. These results suggest that even when instituted as long as 3 hours after coronary occlusion, intraaortic balloon pumping results in significant reduction in infarct size and, it might be speculated, the mortality and morbidity associated with acute myocardial infarction may also be decreased.

Angina Pectoris↗
PubMed1978

Hypertension following coronary artery bypass graft surgery: comparison of hemodynamic responses to nitroprusside, phentolamine, and converting enzyme inhibitor.

Sustained systemic hypertension (mean arterial pressure 119 +/- 4 mm Hg) developed in 39 patients undergoing coronary artery bypass graft (CABG) surgery. In groups of patients with comparable mean arterial pressure, left ventricular filling pressure, heart rate, and cardiac output, treatment with sodium nitroprusside (NP) in 20 patients, phentolamine (PH) in 10 patients and nonapeptide converting enzyme inhibitor (CEI) in nine patients uniformly lowered mean arterial pressure by 26, 21, and 20%, respectively. Cardiac output increased during NP (5.7 +/- 0.1 to 6.4 +/- 0.3 L/min, P < 0.0005) and after CEI (5.7 +/- 0.4 to 7.4 +/- 0.5 L/min, P < 0.0005) but not after PH (5.7 +/- 0.3 to 5.9 +/- 0.3 L/min, P > 0.05). Left ventricular filling pressure decreased in all groups (P < 0.005), but heart rate increased during NP (91.3 +/- 2.4 to 98.4 +/- 2.2 beats/min, P < 0.0005 and after PH (95.5 +/- 2.1 to 99.2 +/- 3.0, P < 0.005), while it was unchanged after CEI P > 0.05). Of the nine patients with CABG hypertension who received CEI, seven exhibited a mean decrease in arterial pressure of 18.5 +/- 3.4%, while in the remaining two patients, mean arterial pressure was decreased only 3.4%. In the former, the pretreatment mean plasma renin activity (PRA) was 7.5 +/- 2.4 ng/ml/hr, while in the latter, mean PRA was 1.3 ng/ml/hr.

Adult↗