Minimally invasive coronary artery bypass surgery without cardiopulmonary bypass.

OBJECTIVE: To report on the initial results of minimally invasive direct coronary artery bypass surgery (MIDCAB) without cardiopulmonary bypass. This is a potential alternative to conventional coronary artery bypass graft surgery, recently introduced to Australia. DESIGN: Prospective survey of patient data. SETTING: Royal Melbourne Hospital campus, Melbourne, Victoria, July 1996 to June 1997. PATIENTS: The first 23 consecutive patients to have a MIDCAB procedure without cardiopulmonary bypass via a small left thoracotomy. The left anterior descending coronary artery was revascularised with the left internal mammary artery. All patients had either recurrent stenosis after previous angioplasty or anatomy unsuitable for angioplasty. OUTCOME MEASURES: Operative morbidity and mortality; graft patency; and patient symptom relief and reoperation rates. RESULTS: Mean age of patients was 57.9 years (range, 29-81), and mean follow-up was 4.0 months (range, 1-10). There was no operative mortality, cardiac infarction or stroke. Mean postoperative stay in the Intensive Care Unit was 30.7 hours and in hospital, 5.3 days. Only one patient needed a blood transfusion (packed red cells). Initial patency of the grafts was confirmed by either angiography (five) or continuous pulse-wave Doppler (23). One patient underwent angioplasty for a stenosis distal to the anastomosis, and two patients (9%) required reoperation for recurrent angina. CONCLUSIONS: MIDCAB can be performed safely, and patient recovery is faster than after conventional coronary artery surgery.

The effects of cardiopulmonary bypass on total and unbound plasma concentrations of propofol and midazolam.

OBJECTIVE: To examine the effects of cardiopulmonary bypass (CPB) on total and unbound plasma concentrations of propofol and midazolam when administered by continuous infusion during cardiac surgery. DESIGN: Prospective clinical study. SETTING: University hospital. PARTICIPANTS: Twenty-four adult patients undergoing cardiac surgery. INTERVENTIONS: Patients received either propofol or midazolam to supplement fentanyl anesthesia. Twelve patients received a propofol bolus (1 mg/kg) followed by an infusion of 3 mg/kg/hr. A second group received midazolam, 0.2 mg/kg bolus, followed by an infusion of 0.07 mg/kg/hr. MEASUREMENTS AND MAIN RESULTS: Blood sample were collected from the radial artery cannula at 0, 2, 4, 8, 8, 10, 15, 20 minutes and then every 10 minutes before CPB, at 1, 2, 3, 4, 6, 10, 15, 20 minutes and then each 10 minutes during CPB. On weaning from CPB samples were collected at 0, 5, 10 and 20 minutes. Plasma binding, total and unbound propofol and midazolam concentrations were determined by ultrafiltration and high-pressure liquid chromatography (HPLC). CPB resulted in a fall in total propofol and midazolam plasma concentrations, but the unbound concentrations remained stable. The propofol unbound fraction increased from 0.22 +/- 0.06% to 0.41 +/- 0.17%. The midazolam unbound fraction increased from 5.6 +/- 1.0% to 11.2 +/- 2.1%. CONCLUSIONS: Unbound concentrations of propofol and midazolam are not affected by cardiopulmonary bypass. Total intravenous anesthesia algorithms do not need to be changed to achieve stable unbound plasma concentrations when initiating CPB.

Cardiac arrhythmia surgery.

Cardiac arrhythmia surgery has changed dramatically in the past several years, as indicated by the articles published during the past year dealing with the surgical treatment of supraventricular and ventricular arrhythmias. With the increasing use of radiofrequnecy ablation for the treatment of arrhythmias, the Maze procedure for the cure of atrial fibrillation will undoubtedly be the most commonly performed supraventricular arrhythmia procedure; the results thus far have been excellent. The use of implantable cardioverter-defibrillators as therapy for ventricular tachycardia and sudden cardiac death has allowed for more optimal selection of patients for direct ventricular tachycardia surgery, with the result that surgical mortality for curative procedures is 4%, with excellent long-term survival and freedom from arrhythmia recurrence. Finally, use of the implantable cardioverter-defibrillator as a bridge to cardiac transplantion has been examined as well, with promising intermediate-term results.