Subtotal median sternotomy for heart surgery.

OBJECTIVE: Many approaches for minimally invasive heart surgery are available. Although they have many advantages, inadequate exposure, mammary artery injury and special tool requirements are known problems. Subtotal median sternotomy (SMS) was developed to overcome such limitations. Comparing the SMS with the standard sternotomy (SS) is the purpose of this study. METHODS: SMS was used in 210 patients (group I) requiring coronary artery bypass grafting and or valvular surgery. This was compared with another 210 patients (group II) in which SS was used. The technical difficulties, incisional discomfort, wound infection, patient satisfaction and hospital stay are the comparison criteria. RESULTS: (1) SMS takes an average of 24 min longer, P<0.15. (2) Incisional discomfort graded (I 'least' to III 'greatest'), group I: (27 Grade I, 176 Grade II, seven Grade III). Group II: (21 Grade I, 183 Grade II, six Grade III), P<0.1. (3) Wound infection: two superficial, two deep in group I, four superficial and one deep in group II, P<0.06, (4) 99% satisfaction and 5.4 days mean hospital stay in group I, 63% and 7.1 days in group II, P<0.01 and <0.03, respectively. CONCLUSION: When comparing the SMS technique with the SS: (1) SMS has statistically significant better patient satisfaction; (2) can be very cost effective due to the short hospital stay and the absence of a need for special instruments.

Midterm results with the Sorin Monostrut heart valve prosthesis.

OBJECTIVE: To monitor the hematological and clinical sequelae of a single tilting disc cardiac valve prosthesis. DESIGN: Prospective nonrandomized trial. SETTING: University teaching hospital. PARTICIPANTS: All patients receiving a single mechanical cardiac valve prosthesis were offered the Sorin Monostrut valve if they met the criteria for valve use. Seventy-five per cent of the patients entered were in New York Heart Association (NYHA) functional class III or IV. One hundred and forty-seven patients were subsequently followed at three months and then yearly after valve implantation for seven years. MAIN OUTCOME MEASURES: At one year, preoperative indexes of hemolysis were compared with three-month and one-year postoperative values. Actuarial curves for survival, freedom from cerebrovascular events and explantation were constructed for the seven-year follow-up period. RESULTS: Hemolysis, as measured by lactate dehydrogenase values, commonly occurs preoperatively, remaining significantly elevated three months and one year following valve implantation. Serum haptoglobin was normal preoperatively but was significantly low at one year. Anemia was uncommon and most patients had normal reticulocyte counts at one year. At three years, 81% of patients were in NYHA functional class I. CONCLUSIONS: Midterm results show that this valve is structurally reliable and meets all current requirements for a safe mechanical valve.

Light versus heavy sedation after cardiac surgery: myocardial ischemia and the stress response. Maritime Heart Centre and Dalhousie University.

UNLABELLED: The influence of light versus heavy sedation after coronary artery bypass graft (CABG) surgery on the development of postoperative myocardial ischemia has not been described. After uncomplicated CABG surgery, 50 patients were randomly assigned to receive LOW (n = 24; target Ramsay Sedation Score [RSS] = 2) or HIGH (n = 26; target RSS = 4) sedation with propofol. Analgesia was provided to maintain a visual analog scale (VAS) pain score <7. Myocardial ischemia was identified perioperatively using continuous 3-lead Holter monitoring. By measuring creatine kinase (CK) MB levels preoperatively, at entry to the intensive care unit (ICU), and every 12 h for 48 h; and by obtaining serial 12-lead electrocardiograms (ECG) (preoperatively; 2, 4, 12, 24, and 48 h after ICU admission, 8:00 AM the morning after surgery; and 5 min pre- and postextubation), myocardial infarction was identified. Endocrine stress response was assessed by measuring serum cortisol levels preoperatively, on admission to the ICU, and 24 h postoperatively. In a subset of patients (LOW n = 10, HIGH n = 11), plasma and urinary catecholamine levels were also measured. There were no between-group differences in demographics, operative course, hemodynamic variables, or cortisol levels while in the ICU. The VAS pain score and target RSS were achieved and sustained, and they differed between groups. There were three myocardial infarctions in each group by CKMB criteria alone. No ECG-identifiable myocardial infarction occurred. The ST segment versus time curve (LOW 187 +/- 295 versus HIGH 1071 +/- 2137 mm/min) differed between groups. Urinary and plasma catecholamine levels were similar between groups over the observation period. We conclude that the use of a reduced sedation regimen in combination with adequate analgesia did not result in an increased endocrine stress response or risk of myocardial ischemia. IMPLICATIONS: This randomized study of patients after coronary artery bypass surgery examined whether light (versus heavy) sedation with propofol in the intensive care unit was associated with an increased degree of myocardial ischemia. Using techniques to detect myocardial ischemia, including Holter monitoring, electrocardiogram, and myocardial enzyme measurements, no differences were found. We conclude that light sedation does not increase the endocrine stress response or the risk of myocardial infarction.

Does pulsatile flow improve glucose tolerance during extracorporeal circulation.

The present study was designed to determine the effect of pulsatile glow on glucose tolerance during cardiac surgery. Twenty patients were divided into two equal groups; ten patients receiving non-pulsatile bypass and the remaining patients receiving pulsatile flow. Patients receiving pulsatile flow had significantly lower systemic resistance in the intensive care unit. Glucose tolerance, however, was similar in both patient groups. Insulin secretion was impaired and serum glucose remained elevated throughout the period of extracorporeal circulation. We conclude from this study that glucose tolerance is unaffected by pulsatile flow.

Suppression of renin production in patients undergoing coronary artery bypass.

Twenty patients undergoing elective myocardial revascularization for coronary insufficiency were divided into two equal groups. In 10 patients, propranolol was discontinued 24 hours before operation while the remaining patients received propranolol until the day of operation. Plasma renin was elevated in the intensive care unit in the control group (p < 0.05) whereas patients receiving propranolol did not demonstrate significant elevation of plasma renin. Systemic vascular resistance was elevated in both groups in the intensive care unit (p < 0.05) and was associated with hypertension as defined by a blood pressure of greater than or equal to 160/100 mm Hg in 80% of the control patients and 70% of patients receiving propranolol. We conclude from this study that renin metabolism does not contribute significantly to the production of hypertension following coronary artery operation.