Effects of intraaortic balloon pumping on mitral flow dynamics in patients with coronary artery bypass operations.

We evaluated the improvement in left ventricular function in 26 patients after coronary artery bypass grafting who were treated with intraaortic balloon pumping (IABP). Mitral flow velocity-time integral in the rapid filling phase (IntR) and that in the atrial contraction phase (IntA), the sum of IntR and IntA (IntR+IntA), and the ratio of IntA to IntR (IntA/IntR) were calculated with patients on and off balloon pumping (IABP ON-OFF test). IABP increased IntR and IntR+IntA, decreased IntA/IntR, and did not change IntA, suggesting that a decreased afterload or augmented coronary perfusion improves left ventricular relaxation. When the balloon inflated on every other beat (IABP 1:2 test), IntR and IntR+IntA increased without balloon assist, IntA/IntR decreased off IABP, and IntA did not change. The afterload reduction or augmented coronary perfusion on the previous beat with IABP might help ventricular filling on the next beat without balloon assist. A drastic decrease in IntR after IABP stopped indicated the need to continue IABP. Since the change in IntR during IABP ON-OFF test was significantly correlated with that in IntR during IABP 1:2 test, the change in IntR during IABP 1:2 test could help to predict the optimal time of weaning.     

Effects of nitroglycerin on the graft flow during aortocoronary bypass surgery

The effects of an intravenous infusion of nitroglycerin on the hemodynamics and bypass graft flow to left coronary artery were studied in sixteen patients during coronary artery surgery. Systolic blood pressure, cardiac output and left ventricular minute work were not affected by 0.2 microgram/kg/min of nitroglycerin but graft flow volume especially diastolic graft flow increased significantly and the characteristics of flow velocity waveform in the graft became more diastolic predominant. By 1 microgram/kg/min of nitroglycerin a significant decrease in systolic blood pressure, cardiac output and graft flow were recognized, however diastolic graft flow was preserved despite of a decrease in left ventricular minute work. These findings demonstrate that nitroglycerin can be safely administered intravenously during aortocoronary bypass surgery, and suggest that nitroglycerin improves the balance of myocardial oxygen demand and supply, and relieves myocardial ischemia.     

Acute thoracic aortic thrombosis after intra-aortic balloon pumping.

We present two transesophageal echocardiographic images of a patient with acute myocardial infarction, demonstrating a large thrombus attached to the thoracic aortic wall, considered to be a complication of intra-aortic balloon pumping. The patient had received the device because of hemodynamic instability due to an infarct-related ventricular septal defect. Clinical manifestations which led to the diagnosis of thromboembolism were abdominal pain and deterioration of renal function, without signs of limb ischemia.     

Isosorbide dinitrate and intra-aortic balloon pumping in preinfarctional angina. Effects on central circulatory dynamics.

The dynamics of the central circulation were measured by a radionuclidic technique in 18 men with high-risk preinfarctional angina who received therapy with isosorbide dinitrate (n equals 18), intra-aortic balloon pumping (n equals 8), or both (n equals 8). Administration of 5 mg of isosorbide dinitrate sublinqually was associated with a reduction in stroke volume index (SVI), cardiac index (CI), systemic arterial blood pressure, and left ventricular end-diastolic volume (LVEDV) and with increased left ventricular ejection fraction (LVEF). Intra-aortic balloon pumping did not alter SVI or CI, but decreased systolic blood pressure and LVEDV and increased LVEF and diastolic blood pressure. The combination of therapy with isosorbide dinitrate and intraaortic balloon pumping resulted in decreased SVI, systolic blood pressure, and LVEDV and increased LVEF. Thus, therapy with isosorbide dinitrate reduced left ventricular preload, and intra-aortic balloon pumping reduced blood pressure, which resulted in a decreased LVEDV and an increase in LVEF. Therapy with isosorbide dinitrate and intra-aortic balloon pumping act to alter central circulatory dynamics in favor of reducing myocardial oxygen demand.     

Influences of intra-aortic balloon pumping on peripheral hemodynamics

The influences of intra-aortic balloon pumping (IABP) on peripheral dynamics were assessed by Doppler echocardiography. The subjects were 20 patients requiring IABP support, postoperatively, to control low cardiac output state. The flow velocity integral in systole (Int S) and that in diastole (Int D) were measured from left common carotid, superior mesenteric, and terminal aortic flow pattern, and the sum of Int S and Int D (Int S + Int D) was calculated with and without balloon pumping. 1) IABP increased cardiac output significantly (p less than 0.01). 2) Common carotid flow: IABP increased Int S significantly (p less than 0.01), but neither Int S nor Int S + Int D changed significantly with IABP. 3) Superior mesenteric flow: IABP increased Int D significantly (p less than 0.01), but both Int S and Int S + Int D remained unchanged with IABP. 4) Terminal aortic flow: None of Int S, Int D and Int S + Int D changed significantly with IABP. These results suggest that the carotid area can receive much of the increase in cardiac output in systole with IABP, and that the superior mesenteric area can receive much of the volume of blood displaced in the aorta by balloon inflation in diastole.     

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.     

Reoperation for angina after previous aortocoronary bypass surgery

A retrospective study was carried out of the outcome of 102 patients who underwent a second operation for myocardial revascularisation, necessitated by persistence or recurrence of intractable angina after their first coronary bypass procedures. Operative mortality was 2%. During follow up of the survivors (mean interval 36.4 months) five died, two after further operation, and five underwent further surgery. Sixty eight patients reported an improvement in their symptoms, 57 of whom claimed to have little or no angina. Less favourable results were recorded for those patients reviewed with longer follow up. No useful indicators of prognosis were identified. The problem of angina in patients who have already received bypass grafts is likely to increase as more revascularisation surgery is performed. Reoperation offers a reasonable prospect of helping some of these patients, but not all will be suitable. Their long term prognosis remains uncertain.     

Effect of pulsatile and nonpulsatile flow during cardiopulmonary bypass on left ventricular ejection fraction early after aortocoronary bypass surgery

Although aortocoronary bypass graft has successfully relieved angina in most patients, concern has been expressed about possible deterioration or failure of improvement of left ventricular performance. With use of intraaortic balloon pumping to produce pulsatile flow during cardiopulmonary bypass, left ventricular ejection fraction and end-diastolic volume index were compared in a consecutive series of 40 men undergoing elective aortocoronary bypass, 20 of whom had pulsatile flow and 20 who had mean flow during cardiopulmonary bypass. Left ventricular ejection fraction and end-diastolic volume index were measured before and 1 to 12 days after operation using a collimated scintillation probe and indium^113m. In the group receiving nonpulsatile flow the ejection fraction decreased from 52.2 ± 2.9 percent (mean ± standard error of the mean) to 38.7 ± 3.2 percent on the first postoperative day and 43.0 ± 3.4 percent on the 10th day (P < 0.001). In the group receiving pulsatile flow, the ejection fraction increased from 51.4 ± 3.0 percent to 61.6 ± 3.4 percent on day 1 and 65.8 ± 2.9 percent on day 10 (P < 0.001). Three of 20 (15 percent) in the group with nonpulsatile flow had an increase of ejection fraction compared with 17 of 20 (85 percent) in the group given pulsatile flow. Left ventricular end-diastolic volume index was not significantly altered in either group. Two men (10 percent) in each group had post-operative myocardial infarction. The ejection fraction increased despite infarction in both patients given pulsatile flow but decreased in both patients with infarction given mean flow. In a series of 235 patients intraoperative infarction occurred in 8 of 109 patients given pulsatile flow (incidence 7.3 percent) but in 14 of 126 patients given mean flow (incidence 11.1 percent) (P < 0.05). These results suggest that pulsatile flow during cardiopulmonary bypass (1) improves left ventricular ejection fraction in the early postoperative period in patients undergoing aortocoronary bypass and (2) may enhance myocardial preservation in these patients.     

Disappearance of abnormal Q waves after aortocoronary bypass surgery

Sixty-one patients were selected from 100 consecutive patients undergoing aortocoronary artery bypass. The number of vessels diseased as defined by coronary arteriography and the number of bypass grafts were recorded. Review of the preoperative electrocardiograms showed an infarct pattern in 26 of the 61 patients and analysis of the postoperative electrocardiograms revealed loss of abnormal Q waves in 3 of the 26. The pre- and postoperative clinical course of these three patients is analyzed and the extent of their coronary artery disease and number of bypass grafts compared with those of the 23 patients who had persistence of the infarction pattern and the 17 patients who manifested new Q waves. Possible explanations for the disappearance of abnormal Q waves are discussed.     

Efficacy of intra-aortic balloon pumping for failing Fontan circulation

The Fontan circulation occasionally cannot be sustained by currently available medical treatment. In these circumstances, mechanical assistance to the Fontan circulation should be considered. We have experienced three cases where Fontan circulation was assisted by intra-aortic balloon pumping (IABP). The hemodynamic improvement and weaning from IABP were successfully achieved in all cases. One patient survived the serious postoperative course with the aid of IAPB, and two patients died following multiorgan failure, though the circulation had eventually been re-established. By studying the postoperative hemodynamics assisted by IABP, it is concluded that IABP is a reasonable, efficacious strategy to support and to re-establish the failing Fontan circulation, though the changes in hemodynamic variables will not immediately coincide with IABP application.     

Analysis of clinical outcomes of intra-aortic balloon pump during coronary artery bypass surgery

An intra-aortic balloon pump (IABP) increases coronary blood flow and reduces left ventricular afterload.1-3 It helps to increase the necessary amount of time for heart recovery in low cardiac output syndrome following a cardiopulmonary bypass (CPB) or ischaemic events. In earlier reports, researchers had suggested that postoperative heart failure was the single indication for IABP support.1,2 However, these indications have widened, and the use of IABP support has recently become more common.Frequently reported complications of IABP include bleeding, aorto-iliac injury and thrombocytopenia.4,5 In-hospital mortality and early mortality of patients requiring IABP support is high, ranging from 26 to 50%, due to the cardiac problems that initially led to the need for this support.6,7The elderly population is continuously increasing across the globe. Parallel with this increase, the number of older patients being referred for coronary artery bypass grafting (CABG) has also increased.8 Although several studies have shown a significant increase in surgical mortality of elderly patients,9 there have been no studies regarding clinical outcomes of IABP in elderly patients.In the present study, we aimed to analyse and compare older with younger patients, regarding clinical features, postoperative complications, intensive care unit and hospital stays, and morbidity and mortality rates in patients who had undergone CABG surgery and required IABP support.     

Reoperation for angina after previous aortocoronary bypass surgery.

A retrospective study was carried out of the outcome of 102 patients who underwent a second operation for myocardial revascularisation, necessitated by persistence or recurrence of intractable angina after their first coronary bypass procedures. Operative mortality was 2%. During follow up of the survivors (mean interval 36.4 months) five died, two after further operation, and five underwent further surgery. Sixty eight patients reported an improvement in their symptoms, 57 of whom claimed to have little or no angina. Less favourable results were recorded for those patients reviewed with longer follow up. No useful indicators of prognosis were identified. The problem of angina in patients who have already received bypass grafts is likely to increase as more revascularisation surgery is performed. Reoperation offers a reasonable prospect of helping some of these patients, but not all will be suitable. Their long term prognosis remains uncertain.