Aram Smolinsky

Platelet protection by low-dose aprotinin in cardiopulmonary bypass: Electron microscopic study

To evaluate the effect of low-dose aprotinin during cardiopulmonary bypass on platelet function and clinical hemostasis, 30 patients undergoing various cardiopulmonary bypass procedures employing bubble oxygenators were randomized to receive either low-dose aprotinin (2 x 10(6) KIU in the cardiopulmonary bypass priming solution, 15 patients [group A]) or placebo (15 patients [group B]). Blood samples were collected before and after cardiopulmonary bypass to assess platelet count and aggregation on extracellular matrix, which was studied by a scanning electron microscope. On a scale of 1 to 4 preoperative mean platelet aggregation grades were similar in both groups (3.8 +/- 0.5 and 3.5 +/- 0.5 for groups A and B, respectively). Postoperatively, platelet aggregation on extracellular matrix decreased slightly in group A (2.8 +/- 1.3; p < 0.01) and significantly in group B (1.3 +/- 0.5; p < 0.001). Eleven of the 15 patients in group A remained in aggregation grade 3 or 4 compared with none of the group B patients. Platelet count was similar in both groups preoperatively and postoperatively. Total 24-hour postoperative bleeding and blood requirement were lower in the aprotinin group (487 +/- 121 mL and 2.3 +/- 1.0 units) than in the placebo group (752 +/- 404 mL and 6.8 +/- 5.1 units; p < 0.01). These results show that the use of low-dose aprotinin during cardiopulmonary bypass provides improved postoperative hemostasis, which might be related to the protection of the platelet aggregating capacity.

Predictors of early and overall outcome in coronary artery bypass without cardiopulmonary bypass.

OBJECTIVE Cardiopulmonary bypass in coronary artery bypass graft operations may adversely affect the outcome especially in high-risk patients. The purpose of this study is to evaluate results of coronary artery bypass performed without cardiopulmonary bypass, in a relatively high-risk cohort, and to identify predictors of unfavorable outcome. METHOD Three hundred and thirteen (313) patients, 246 (79%) of whom had high-risk conditions, who have a coronary anatomy suitable for coronary artery bypass surgery without cardiopulmonary bypass, underwent this procedure between December 1991 and July 1995. Mean number of grafts/patient was 1.8 (1-5), and only 71 patients (23%) received a graft to the circumflex coronary system. RESULTS Early unfavorable outcome events included operative mortality (12 patients, 3.8%), nonfatal perioperative myocardial infarction (eight patients, 2.6%), emergency reoperation (three patients, 0.9%), sternal infection (five patients, 1.6%), and nonfatal stroke (two patients, 0.6%). Multivariate analysis revealed angina pectoris class IV (odds ratio 5.4) and age > or = 70 years (odds ratio 5.0) as independent predictors of early mortality. Preoperative risk factors such as repeat coronary artery bypass grafting (50 patients, 16%), ejection fraction < or = 0.35 (85 patients, 27%), acute myocardial infarction (86 patients, 28%), cardiogenic shock (ten patients, 3.2%), chronic renal failure (25 patients, 8%), chronic obstructive pulmonary disease (20 patients, 6%), and peripheral vascular disease (51 patients, 16%) did not increase early mortality. During 33 months of follow-up (range 1-57 months), there were 42 deaths, at least 16 cardiac-related (one and four years actuarial survival of 90% and 76% respectively), and 39 patients (12.5%) in whom angina returned. Calcified aorta (odds ratio 2.6) and old myocardial infarction (odds ratio 1.8) were independent predictors of overall unfavorable events. CONCLUSIONS Coronary artery bypass grafting without cardiopulmonary bypass can be performed with relatively low operative mortality in certain high-risk subgroups of patients; however, an increased risk of graft occlusion is a potential disadvantage. This procedure should therefore be considered only for patients with suitable coronary anatomy, in whom cardiopulmonary bypass poses a high risk. Although the risk of stroke is relatively low, the procedure is still hazardous for patients aged 70 years and over.

Multidisciplinary intervention for control of diabetes in patients undergoing coronary artery bypass graft (CABG)

In Israel, as elsewhere, diabetes mellitus is highly prevalent among patients undergoing coronary artery bypass graft (CABG). The bulk of evidence, derived retrospectively, suggests that poor control of diabetes predisposes to complications of CABG and increases mortality; but the findings in a number of studies fail to support that impression. Anticipating a prospective investigation designed to resolve this issue, we have carried out a preliminary study of 147 consecutive patients with diabetes who were hospitalized for elective CABG during 1998. Our objective was to determine how well and how often diabetes could be controlled in accordance with selected metabolic goals in the brief interval between hospital admission and surgery and during the operation itself and in the postoperative period. The task was undertaken by a multidisciplinary team, in cooperation with the Department of Cardiac Surgery. The metabolic goals were: fasting blood glucose consistently between 65-140 mg/dl before and after surgery and 120-180 mg/dl at the time of surgery; and postprandial blood glucose consistently <180 mg/dl. These goals were achieved in 18.1% of fasting blood glucose measurements before and after surgery, 22.1% of preprandial and 14.6% of postprandial blood glucose levels consistently <180 mg/dl. There were no clinical episodes of hypoglycemia. Due to the low incidence of major infection related complications (deep sternal wound infection in only 3 patients (2.0%)) no significant statistical conclusions on the relations between glucose control and these complications could be drawn. The means of all values of FBG and of hemoglobin A1c were significantly higher among patients with complications (n=49) than in those without (P=0.01).

Effects of Antegrade versus Combined Antegrade/Retrograde Cardioplegia on Postoperative Septal Wall Motion in Patients Undergoing Open Heart Surgery

To evaluate the influence of two techniques of myocardial protection on septal wall motion (SWM) and left ventricular ejection fraction, 21 patients with a normal SWM underwent surgery using either conventional antegrade cardioplegia (group I, n = 9) or combined antegrade/retrograde cardioplegia (group II, n = 12). The patients were assessed pre- and postoperatively by radionuclide ventriculography. A resting thallium-201 study was performed in patients (n = 6) with a postoperatively abnormal SWM: in 2 of 9 (22%) in group I and in 4 of 12 (33%) in group II (p = NS). The left ventricular ejection fraction was similar in both groups before surgery (57 +/- 3% in group I vs. 57 +/- 8% in group II; p = NS) and did not change significantly after surgery. All 6 patients with an abnormal SWM had a normal septal thallium-201 uptake. Thus, (1) an abnormal SWM after cardiac surgery is common: (2) it is not due to perioperative ischemia or infarction, and (3) neither the incidence of an abnormal SWM not the global left ventricular function is influenced by the addition of retrograde cardioplegia during open heart surgery.

Correction of tetrad of fallot with reduced incidence of right bundle branch block

In 20 patients who underwent a modified surgical repair of tetrad of Fallot complete right bundle branch block developed in only 8 (40 percent). Standard and intraoperative conduction studies indicated that in these patients the right bundle branch block was due to injury of the right bundle branch near the ventricular septal defect (proximal right bundle branch block). The modified operative technique is aimed at minimizing the injury to the right ventricle and it includes a significantly shorter than usual ventriculotomy incision and avoidance of the septal (moderator) band during infundibulectomy. Intra- and postoperative hemodynamic studies of these patients revealed that relief of the right ventricular outflow obstruction was optimal.

TREATMENT OF NOCTURNAL ANGINA WITH 10° REVERSE TRENDELENBURG BED POSITION

The effect of 10 degrees reverse Trendelenburg tilt of the bed was studied in ten patients with refractory nocturnal angina on 2 consecutive nights before aortocoronary bypass surgery. For the control night the bed was placed in the semi-orthopnoeic position, and for the test night it was put in the reverse Trendelenburg position. This position significantly reduced central venous pressure, diastolic pulmonary artery pressure, the number of isosorbide dinitrate tablets taken sublingually, and the number of angina episodes per night. Reverse Trendelenburg tilt of the bed therefore seems effective for relief of nocturnal anginal pain.

Long-term Arm Morbidity after Radial Artery Harvesting for Coronary Bypass Operation

BACKGROUND The use of the radial artery (RA) in coronary bypass operations has become increasingly popular in recent years, but there is almost no documentation regarding the midterm and long-term arm complications. METHODS Between January 1 and December 31, 1998, 109 patients underwent operations for myocardial revascularization employing a pedicled RA as 1 of the coronary grafts. The patients were surveyed for subjective arm morbidities at 2 times during their follow-up: short term (mean, 7 months postoperatively; range, 0.3-14 months) and long term (mean, 49 months postoperatively; range, 46-57 months). RESULTS At the short-term follow-up, 33 (33.3%) of the patients had some complaints regarding the arm that was operated on, with 4 (4%) of the patients reporting arm disability with complaints that focused on pain (11, 11%), numbness (15, 15%), and parasthesias (12, 12%). At the longterm follow-up, only 9 patients (10.5%) still experienced some sort of inconvenience with the arm that was operated on, with 1 case of functional disability, 4 complaints (4.6%) of residual parasthesias, and 1 report (2.3%) each of pain or numbness. All but 2 of the patients with complaints at the short-term follow-up reported amelioration of symptoms at the long-term follow-up. CONCLUSION It appears that severe arm disability early after RA harvesting is likely to dissolve with time. Our favorable late follow-up results support the continuation of the employment of the RA as a conduit for coronary artery bypass grafting operations.