Enhanced coronary flow velocity during intra-aortic balloon pumping assessed by transthoracic Doppler echocardiography.

OBJECTIVES: The study was done to determine potential utility of measuring coronary flow velocity (CFV) by transthoracic Doppler echocardiography (TTDE) during intra-aortic balloon pumping (IABP). BACKGROUND: Use of IABP has been shown to increase CFV assessed by an invasive technique. The CFV in the left anterior descending coronary artery (LAD) can be measured by TTDE. METHODS: Coronary flow velocity in the distal LAD by TTDE was measured in 40 critically ill patients requiring IABP. All patients received emergency coronary angiography. Both CFV and pressure data were obtained during 1:2 balloon pumping. RESULTS: Adequate diastolic CFV recording was obtained in all patients. The IABP decreased systolic pressure and increased diastolic pressure. Average peak diastolic flow velocity and diastolic velocity time integral was 19 +/- 11 cm/s and 7.7 +/- 4.4 cm with non-augmented beat. These values were increased significantly (61 +/- 38%, 59 +/- 35%, p < 0.001) with augmented beat. Significant correlation was noted between % diastolic pressure augmentation and % increase in diastolic CFV (r = 0.62 to 0.69, p < 0.001). There was no significant difference in flow enhancement during IABP, irrespective to the proximal LAD stenosis severity (severe stenosis: 73 +/- 70%; intermediate stenosis: 61 +/- 29%; no significant stenosis: 58 +/- 29%; p = NS, analysis of variance). By continuous recording of CFV, the optimal timing of balloon control could be adjusted to maximize flow velocity during augmentation. CONCLUSIONS: Use of TTDE can be employed in monitoring CFV augmentation during IABP. The IABP produced significant distal flow enhancement even in patients with critical proximal stenosis. This totally noninvasive approach may help to optimize the benefits of IABP for coronary flow augmentation.

Simultaneous assessment of wall motion and coronary flow velocity in the left anterior descending coronary artery during dipyridamole stress echocardiography.

OBJECTIVES: This study was designed to assess the feasibility and clinical meaning of simultaneous assessment of wall motion and coronary flow velocity (CFV) reserve in the left anterior descending coronary artery (LAD) by transthoracic approach for detecting LAD stenosis during dipyridamole stress echocardiography. BACKGROUND: Coronary flow reserve plays an important role, which can be evaluated by transthoracic Doppler echocardiography during vasodilator stress. METHODS: Dipyridamole stress test was performed in 110 patients with known or suspected coronary artery disease. CFV in the distal LAD was obtained at baseline and after dipyridamole infusion, and wall motion was also assessed up to the administration of atropine, if required. All patients underwent quantitative coronary angiography within 2 days of the stress test, and significant LAD stenosis was defined as > 50% stenosis. RESULTS: The success rate of both measurements was 92%. CFV reserve < 2 had a higher sensitivity (94% vs 72%, P <.01) and a lower specificity (65% vs 95%, P <.01) than wall-motion assessment for detecting significant LAD stenosis, and diagnostic accuracy between 2 methods was comparable (81% vs 82%). A total of 69 patients (73%) showed concordant results of the 2 methods, and diagnostic accuracy for detecting significant LAD stenosis was high (94%) in this subset of patients. CONCLUSIONS: The simultaneous assessment of CFV and wall motion was feasible in the majority of cases during dipyridamole stress echocardiography. Although diagnostic accuracy between the 2 tests was comparable, concordant results of the 2 methods provided accurate diagnosis in detecting significant LAD stenosis.