Flow capacity of the human retrograde internal mammary artery: surgical considerations.

The diastolic flow of the retrograde internal mammary artery (IMA) was calculated in 30 patients and compared with the expected coronary flow of the left ventricle and that of specific branches. Arterial pressure and free flow were measured in the proximal and distal IMA as well as in the superior epigastric and musculophrenic arteries. Systolic and mean arterial pressure were significantly higher in the proximal IMA than in any other site, but diastolic pressure was comparable. Overall and diastolic antegrade IMA flows (77 +/- 6 and 44 +/- 3 mL/min) were significantly greater than the retrograde flows through the distal IMA (18.5 +/- 2 and 11.5 +/- 1 mL/min), musculophrenic artery (13.3 +/- 1 and 7.9 +/- 1 mL/min), and superior epigastric artery (5.3 +/- 0.4 and 3.1 +/- 0.2 mL/min). Only patient-size-related variables correlated significantly with retrograde IMA flow. Diastolic retrograde IMA flow represented 8.5% +/- 0.6% of the expected left ventricle coronary flow and in 12 patients (40%) was greater than the expected flow of at least one posteroinferior coronary artery. Based on these data, the retrograde IMA may adequately perfuse the posterior descending or other posterolateral coronary branches in select patients. Previous measuring of the retrograde flow is mandatory.

[Myocardial revascularization surgery during a developing infarction]. / Cirugía de revascularización miocárdica en el infarto en evolución.

Our results with surgical revascularization for evolving myocardial infarction in 30 patients are analyzed. There were 25 men and 5 women (mean age 55 +/- 10 years), most with unstable angina (80%), which sustained an acute myocardial infarction secondary to either a severe stenosis (23%) or a complete obstruction (77%) of a mayor coronary artery during a diagnostic coronarography (27%) or a percutaneous transluminal coronary angioplasty (73%). The most frequently involved vessels were the left anterior descending and right coronary arteries (11 cases), followed by the left main stem (5 cases) and the circumflex artery (3 cases). Nineteen patients (group I) developed electrocardiographic and/or enzymatic evidence of established myocardial necrosis despite early reperfusion, whereas 11 patients did not (group II). These groups were compared according to different clinical, angiographic, hemodynamic, and operative variables. Group I patients had a more recent disease and a better segmentary contraction. The same variables were compared between the 5 patients with early cardiac death (group III) and the remainder 25 (group IV). Refractory cardiac arrest, jeopardized myocardial mass and coronary perfusion indexes after the infarction-related complication, all were more desfavorable in group III. The ischemic interval between infarction onset and reperfusion was not different between the groups. The potential of surgery for myocardial salvage in the setting of evolving necrosis is emphasized as well as the influence of the magnitude of involved myocardium and its clinical repercussion on early mortality.

[Myocardial revascularization: isoflurane and halothane. Our experience]. / Revascularización miocárdica: isofluorano y halotano. Nuestra experiencia.

The use of isofluorane in coronary patients has been questioned due to the coronary steal syndrome that this agent is said to produce with changes in the myocardial lactate extraction, ST segment changes or T wave inversion. Three hundred fifty nine patients underwent coronary revascularization were studied. The anaesthesia was carried out with halothane (146 patients) or isofluorane (213 patients) as volatile agents of a balanced anesthetic technique based on high doses of narcotics. We found no correlation between the use of isofluorane and ST changes or T wave inversion. The appearance of myocardial infarction between the 2 groups was also no statistically difference (p = 0.61).