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Background: Controversy exists regarding the management of angiographically disease-free saphenous vein grafts at the time of redo coronary artery bypass grafting (CABG). Some authorities favor replacement of these disease-free grafts, arguing that occlusion is likely in the near future. Others believe that these grafts are "biologically privileged" and should not be replaced., Methods: One hundred thirty-two consecutive patients (113 men, 19 women, aged 46 to 88 years, mean 67 years) underwent redo revascularization with one or more angiographically disease-free saphenous vein grafts at the time of redo CABG. Thirty-six patients had the disease-free grafts replaced (R) and 96 did not (NR). The mean interval from the first CABG was 9.25 years., Results: Surgical mortality was comparable in the NR and R groups (5 of 96 or 5.2% versus 3 of 36 or 8.3%, respectively; p < 0.5). Survival at 1 and 3 years was higher in the NR group than the R group (98% versus 80%, and 95% vs. 66% respectively; p < 0.0001). Late myocardial infarction was less common in the NR group than in the R group (12 of 91 or 12.9% versus 12 of 33 or 36.4%; p < 0.003). Recurrent angina was less common in the NR than in the R group (21 of 91 or 23.1% versus 15 of 33 or 45.5%; p < 0.015). Cardiac hospitalization was required less commonly in the NR than in the R group (11 of 91 or 12.1% versus 12 of 33 or 36.4%; p < 0.002). In nondiseased grafts undergoing angiographic evaluation late after redo CABG, rate of new stenosis was lower in NR grafts than in R grafts (2 of 12 or 16.7% versus 2 of 3 or 66.7%; p < 0.05)., Conclusions: With a conservative approach that does not replace nondiseased saphenous vein grafts at redo CABG (1) there is no increase in operative mortality, (2) good late survival is obtained, (3) clinical ischemia related to the NR saphenous vein grafts is uncommon, and (4) NR grafts continue to be patent. We conclude that disease-free vein grafts may not require routine replacement at redo CABG. A randomized study is required for definitive resolution.

Regional and global left ventricular dysfunction caused by coronary artery disease may be reversible in a significant proportion of cases. This fact has important clinical implications. Apart from symptoms of angina and angiographic severity of coronary artery disease, potential for an improvement in left ventricular dysfunction should be taken into account when considering revascularization for the management of patients with coronary artery disease. Because left ventricular function is an important determinant of long-term prognosis in patients with coronary artery disease, identification and appropriate treatment of reversible left ventricular dysfunction may improve prognosis in many patients with significant left ventricular dysfunction. Table 1 describes the impact of myocardial viability in relation to the clinical objectives in various groups of patients with coronary artery disease. The choice of the optimal technique for the detection of myocardial viability is a matter of ongoing debate. There is no consensus in the literature for an optimal investigative approach to predict an improvement in left ventricular function following revascularization. Most of the studies in this field are based on small numbers of patients. Further studies in larger patient populations are needed. This debate is further complicated by the fact that none of the available technologies provides a quantitative estimate of viable myocardium or the extent of improvement that can be expected following revascularization. Currently the choice of technique depends on the clinical question to be answered, the local availability of the technique, and local expertise. Obviously, cost considerations may also play an important role in choice of technique. In patients with chronic stable coronary artery disease in whom reversibility of stress-induced perfusion abnormalities is the question, stress-redistribution-rest Tl-201 imaging may be the preferred modality. In patients with congestive heart failure, in whom reversibility of left ventricular function is the issue, PET imaging or rest Tl-201 imaging may provide the appropriate answer. In post-infarction patients, choice of test may depend on whether detection of residual ischemia or stunned myocardium is the issue.

Due to the complex geometry of the right ventricle, contrast angiography is not ideally suited for determining its volumes and for carrying out volume-based analyses. Nuclear cardiological techniques, being free from this limitation, have played an important role in understanding the right ventricular performance in various disease conditions. This technique is currently in clinical use and can be applied for assessing the role of right ventricular function in various cardiopulmonary diseases.

In summary, nuclear techniques have important roles in both the acute and convalescent phase of MI. Acutely, both myocardial perfusion and ventricular function may be assessed. In patients treated with thrombolytic therapy, perfusion imaging, and metabolic imaging using PET may be able to delineate ischemic myocardium. These techniques are being developed to accurately quantify salvaged myocardium for assessing the efficacy of an acute intervention, and to characterize (functionally) the remaining myocardium for possible further intervention. In the convalescent phase, prognostic information is obtained from both rest and exercise evaluation of ventricular function and reserve, ambulatory monitoring, as well as from the presence of exercise-induced ischemia as documented by quantitative thallium imaging. The results of these studies can be used to determine appropriate management strategies.

Concurrent burst suppression and alpha pattern coma developed in the EEG of a 2-year-old child who suffered a cardiac arrest secondary to hypoxemia from Haemophilus influenza epiglottis. The neurophysiological implications of this association are discussed and the literature pertaining to the role of barbiturates in the production of post-anoxic coma with an alpha pattern and experimental post-resuscitative alpha frequencies is reviewed.

Twenty-three surviving patients who were weaned from cardiopulmonary bypass with intraaortic balloon pump assistance returned for follow-up radionuclide left ventricular (LV) function and thallium 201 perfusion studies at a mean of 23 +/- 3 months following operation. It was found tat despite profound intraoperative myocardial depression requiring intraaortic balloon assistance, 13 patients had no change (within 10%) in the resting LV ejection fraction compared with the preoperative measurement. Among all 23 patients, there was no difference between mean (+/- standard error of the mean) preoperative and postoperative resting LV ejection fraction (48 +/- 4 vs 46 +/- 4%, p = not significant [NS]). Only 11 patients had perioperative myocardial infarction documented by new Q waves in the electrocardiogram, by elevation of creatine kinase-MB fraction, or by defects on thallium 201 imaging not explained by documented myocardial infarction before operation. Overall, postoperative resting LV ejection fraction was not different from the preoperative value in patients with perioperative myocardial infarction (44 +/- 7 vs 47 +/- 5%, p = NS). Postoperative resting LV ejection fraction rose by greater than 10% compared with preoperative values in 4 patients (3 with aortic valve replacement), remained within the 10% limit in 9 patients, and fell by greater than 10% in 10 patients (7 with perioperative myocardial infarction). Only 4 out of 16 patients studied at follow-up with exercise radionuclide studies demonstrated a normal LV response to exercise (greater than 5% increase in LV ejection fraction). Thus, among survivors requiring intraaortic balloon pump assistance for weaning from cardiopulmonary bypass, LV performance at rest is frequently preserved. In addition, 11 of the 23 patients had evidence of perioperative myocardial infarction, indicating a component of reversible intraoperative LV dysfunction.

We studied a patient with an anomalous left coronary artery arising from the pulmonary artery by using conventional angiographic and myocardial imaging techniques. Myocardial imaging with radioactive 201thallium confirmed the significance of resting Q waves, and the defect in anterior perfusion coupled with the presence of thallium in the pulmonary outflow tract during exercise underscored the dynamic nature of the ischemic response to exercise in this syndrome.