Barriers to the universal adoption of bilateral internal mammary artery grafting.

The left internal mammary artery (LIMA) graft is considered the "gold standard" of coronary artery bypass grafting (CABG). This conduit provides increased survival, symptomatic relief, increased freedom from myocardial infarction, and increased freedom from re-intervention when compared to saphenous venous grafting. It has a remarkable long term patency rate with clinical and angiographic outcomes that are unmatched by other conduits. Given the fact that patients often require more than one graft during a coronary revascularization procedure, the prospect of bilateral internal mammary artery (BIMA) grafting has been very appealing to some surgeons. BIMA grafting has been extensively studied via multiple retrospective and prospective cohort studies and findings have indicated that BIMA grafting can have an increased survival benefit when compared to LIMA grafting alone. As a result, this technique has accrued increasing popularity over the course of the last decade. Yet, questions still remain on whether BIMA grafting is the optimal treatment modality for patients in terms of long-term prognosis. There is limited data at the present time from randomized controlled trials and only 4-12% of CABGs performed today utilize BIMA grafting. Concerns regarding perioperative complications, which patient subsets are at higher risks for complications from the technique, and the technical challenges involved in utilizing and teaching the technique have limited its widespread use.

Accurate determination of high-risk coronary lesion type by multidetector cardiac computed tomography.

BACKGROUND: Coronary arteriography (CA) is the standard method to image coronary lesions. Multidetector cardiac computerized tomography (MDCT) provides high-resolution images of coronary arteries, allowing a noninvasive alternative to determine lesion type. To date, no studies have assessed the ability of MDCT to categorize coronary lesion types. HYPOTHESIS: The objective of this study was to determine the accuracy of lesion type categorization by MDCT using CA as a reference standard. METHODS: Patients who underwent both MDCT and CA within 2 months of each other were enrolled. MDCT and CA images were reviewed in a blinded fashion. Lesions were categorized according to the SCAI classification system (Types I-IV). The origin, proximal and middle segments of the major arteries were analyzed. Each segment comprised a data point for comparison. Analysis was performed using the Spearman Correlation Test. RESULTS: Four hundred eleven segments were studied, of which 110 had lesions. The lesion distribution was as follows: 35 left anterior descending (LAD), 29 circumflex (Cx), 31 right coronary artery (RCA), 2 ramus intermedius, 8 diagonal, 4 obtuse marginal and 2 left internal mammary arteries. Correlations between MDCT and CA were significant in all major vessels (LAD, Cx, RCA) (p < 0.001). The overall correlation coefficient was 0.67. Concordance was strong for lesion Types II-IV (97%) and poor for Type I (30%). CONCLUSION: High-risk coronary lesion types can be accurately categorized by MDCT. This ability may allow MDCT to play an important noninvasive role in the planning of coronary interventions.

Improvement of cardiac function persists long term with medical therapy for left ventricular systolic dysfunction.

In certain patients with left ventricular (LV) systolic dysfunction, improvements in cardiac function are seen after initiation of medical therapy; however, the long-term stability of ventricular function in such patients is not well described. We retrospectively analyzed 171 patients who had a baseline ejection fraction of 45% or less, a follow-up echocardiogram at 2 to 12 months after initiation of medical therapy, and a final echocardiogram. We found that 48.5% of the patients demonstrated initial improvements in LV function after initiation of medical therapy, and the improvements appear to be sustained (88% of patients) at 44 +/- 21 months follow-up. A nonischemic etiology and younger age were the only independent predictors of change of LV ejection fraction of 10 or more at a mean 8.4 +/- 3.4 months after optimal medical therapy. Our study revealed a trend toward improved long-term survival in individuals with an early improvement in LV ejection fraction with medical therapy, especially in those with sustained improvement.

Prognostic significance of hemoglobin level in patients with congestive heart failure and normal ejection fraction.

BACKGROUND: Previous studies have shown low hemoglobin (Hb) to have an adverse effect on survival in patients with congestive heart failure (CHF) and reduced left ventricular (LV) ejection fraction (EF); but its effect on survival in patients with CHF and normal EF is not known. HYPOTHESIS: This study sought to determine whether low Hb has an effect on survival in patients with both CHF and normal EF. METHODS: Detailed chart reviews were performed by medical residents on 2,246 patients (48% with normal EF) with a discharge diagnosis of CHF in a large tertiary care hospital from 1990 to 1999. The CHF diagnosis was validated using the Framingham criteria. Mortality data were obtained from the National Death Index. Survival analysis was performed using Kaplan-Meier and Cox regression models. RESULTS: By Kaplan-Meier analysis, low Hb (< 12 gm/dl) compared with normal hemoglobin was associated with a lower 5-year survival in patients with CHF and both normal (38 vs. 50%, p = 0.0008) and reduced (35 vs. 48%, p = 0.0009) EF. Using the Cox regression model, low Hb was an independent predictor of mortality after adjusting for age, gender, renal dysfunction, diabetes mellitus, hypertension, and EF in both groups of patients. CONCLUSION: Low Hb has an independent adverse effect on survival in patients with CHF and both normal and reduced EF in both groups of patients.