Seishi Nakamura

TIMI frame count immediately after primary coronary angioplasty as a predictor of functional recovery in patients with TIMI 3 reperfused acute myocardial infarction

OBJECTIVES The purpose of this study was to evaluate whether higher coronary blood flow, estimated by the corrected Thrombolysis In Myocardial Infarction (TIMI) frame count (CTFC), is related to better functional and clinical outcome after successful percutaneous transluminal coronary angioplasty (PTCA) in patients with acute myocardial infarction (AMI). BACKGROUND Experimental studies have found that functional recovery of the infarcted myocardium was associated with increased blood flow (reactive hyperemia) to the infarcted bed shortly after reperfusion. METHODS We measured CTFC immediately after successful (TIMI 3) primary PTCA in 104 consecutive patients with their first AMI. Wall motion score index (WMSI) and the presence of pericardial effusion were assessed by two-dimensional echocardiography before and one month after PTCA. RESULTS The patients were divided into two groups according to mean CTFC for corresponding coronary artery of the control group: TIMI 3 slow group (45 patients, 40 > CTFC > or = 23) and TIMI 3 fast group (59 patients, CTFC < 23). There were no significant differences in the baseline characteristics and WMSI before reperfusion between the two groups. Improvement of WMSI in the TIMI 3 fast group was significantly greater than that of the TIMI 3 slow group (1.33 +/- 0.52 vs. 0.60 +/- 0.34, p < 0.001). Pericardial effusion and intractable heart failure were observed more frequently in the TIMI 3 slow group than in the TIMI 3 fast group (27 vs. 10%; p < 0.05, 36 vs. 17%; p < 0.05). Corrected TIMI frame count, assessed as a continuous variable, had a significant correlation with the change in WMSI (r = 0.60, p < 0.001) after adjusting for age, gender, history of hypertension, history of diabetes, elapsed time to PTCA, collateral grade, presence of antegrade flow before PTCA and number of diseased vessels. CONCLUSIONS Lower CTFC of the infarct-related artery immediately after PTCA was associated with greater functional recovery; and hence, CTFC can predict clinical and functional outcome in patients with successful PTCA.

Atrial fibrillation in inferior wall Q-wave acute myocardial infarction.

Abstract Although atrial fibrillation (AF) is a relatively common arrhythmia occurring during the course of acute myocardial infarction (AMI), the mechanisms involved in its genesis remain controversial and are mostly focused on the left ventricle and atrium: left ventricular failure, pericarditis and left atrial ischemia.1–4 In contrast, the role of hemodynamic change imposed on the right ventricle and right atrium related to the onset of AF after AMI is poorly understood. Because hemodynamic change of the right ventricle is often observed in inferior AMI, we hypothesized that hemodynamic impairment, audible pericardial friction rub, electrocardiographic evidence of right ventricular AMI and age may be important clinical factors associated with the occurrence of AF. In this study, multivariate analysis was used to assess the clinical settings associated with the occurrence of AF in patients with their first Q-wave inferior AMI.

Early identification of impaired myocardial reperfusion with serial assessment of ST segments after percutaneous transluminal coronary angioplasty during acute myocardial infarction

To evaluate the relation between ST-segment analysis and microvascular reperfusion in patients with acute myocardial infarction (AMI), we studied 51 patients with first AMI who were successfully treated by percutaneous transluminal coronary angioplasty (PTCA). The lead showing the greatest ST-segment elevation on the 12-lead electrocardiogram (ECG) was serially investigated until 24 hours after PTCA. Successful reperfusion was determined by technetium-99m tetrofosmin single-photon emission computed tomography. Impaired reperfusion (group 1: < 4 change in the sum of the defect score from before to immediately after PTCA) was observed in 24 patients, and successful reperfusion (group 2) was observed in 27 patients. Although ST-segment elevation was reduced significantly at 30 minutes after PTCA in group 2 (2.2 +/- 1.4 to 1.7 +/- 1.3 mm, p = 0.01), there was no significant change in group 1 (1.9 +/- 1.9 to 2.4 +/- 1.7 mm). Ten of 14 patients (71%) with persistent ST-segment elevation (DeltaST > 0 mm change in ST segment from before to 30 minutes after PTCA > 0) were in group 1, whereas 23 of 37 patients (62%) with ST-segment resolution (DeltaST < or = 0) were in group 2. The sensitivity and specificity of persistent ST-segment elevation for predicting impaired microvascular reperfusion were 42% and 85%, respectively. Thus, persistent ST-segment elevation 30 minutes after primary PTCA was a highly specific electrocardiographic marker of impaired reperfusion in patients with AMI.

Prevention of contrast-induced nephropathy by chronic pravastatin treatment in patients with cardiovascular disease and renal insufficiency

BACKGROUND Contrast-induced nephropathy (CIN) is known to increase morbidity and mortality of cardiovascular disease. Recent studies have shown statins prevented CIN after contrast media exposure, but optimal statin type and dosage are still unknown. PURPOSE The aims of the present study were to evaluate whether chronic pravastatin treatment before scheduled coronary angiography or percutaneous coronary intervention could reduce the incidence of CIN and to elucidate the factors related to CIN in patients with renal insufficiency. METHODS We studied 431 consecutive patients with renal insufficiency. One hundred ninety-four patients were receiving pravastatin treatment as standard chronic treatment of hypercholesterolemia. Serum creatinine levels were measured at baseline (pre-procedure) and within 48 h after contrast media exposure (peak post-procedure). CIN was defined as an increase in the serum creatinine values of > or = 25% or > or = 0.5 mg/dl after contrast media exposure. Logistic regression analysis was performed to evaluate the important factors related to CIN using four variables: age, pravastatin, pre-procedure serum creatinine, and contrast volume. RESULTS CIN was observed in 36 patients (8.4%). Patients without pravastatin (p<0.01), high level pre-procedure serum creatinine (p<0.01), and high contrast volume (p=0.034) had a significantly higher incidence of CIN. Logistic regression analysis revealed that pravastatin treatment (chi(2)=6.549, p=0.011, odds ratio=0.34), pre-procedure serum creatinine (chi(2)=6.294, p=0.009, odds ratio=2.78), and contrast volume (chi(2)=4.484, p=0.034, odds ratio=1.01) were independently related to the decreased risk of CIN. CONCLUSIONS Chronic pravastatin treatment before contrast media exposure was important for preventing CIN in patients with renal insufficiency. Also, reducing the dose of contrast media was important for preventing CIN in patients with high-baseline serum creatinine levels.

Mixed venous oxygen saturation as a guide to tissue oxygenation and prognosis in patients with acute myocardial infarction

The relation of mixed venous oxygen saturation and the cardiac index to tissue oxygenation and prognosis was investigated in 119 patients with acute myocardial infarction. There was a positive correlation between mixed venous oxygen saturation and the cardiac index in 97 survivors and 22 nonsurvivors, but a significantly lower mixed venous oxygen saturation level at the same level of cardiac index was observed in nonsurvivors compared with survivors. Results of multivariate analysis with mixed venous oxygen saturation and the cardiac index indicated that only mixed venous oxygen saturation was significantly related to survival and to hyperlactacidemia. Oxygen delivery to tissues declined significantly in nonsurvivors because of a lower cardiac index and a lower hemoglobin concentration in these patients than in survivors. However, at the same level of oxygen delivery to tissues, nonsurvivors had a significantly higher rate of oxygen consumption leading to a correspondingly greater decrease in mixed venous oxygen saturation, suggesting that a greater increase in oxygen demand was also observed in nonsurvivors than in survivors. Thus mixed venous oxygen saturation after acute myocardial infarction is a better predictor of hyperlactacidemia and survival than the cardiac index, and this may be associated with an increased oxygen demand and an impaired oxygen transport system in seriously ill patients.

Left ventricular free wall rupture after reperfusion therapy for acute myocardial infarction.

We evaluated the clinical significance of angiographic indexes and pericardial involvement in predicting increased risk of free wall rupture after reperfusion therapy and found that Thrombolysis In Myocardial Infarction (TIMI) <3 flow grade after reperfusion therapy was a significant variable related to the free wall rupture. Moreover, pericardial rub was found to be a significant variable related to TIMI <3 grade flow after reperfusion, which indicates that detection of pericardial rub is one of the clinical signs that predicts inadequate anterograde flow of the infarct-related artery after reperfusion and hence, higher risk for free wall rupture.

The effect of verapamil on the restoration of myocardial perfusion and functional recovery in patients with angiographic no-reflow after primary percutaneous coronary intervention.

ObjectiveAngiographic thrombolysis in myocardial infarction (TIMI) flow grade≤2 after primary percutaneous coronary intervention (PCI), defined as angiographic no-reflow, predicts poor functional recovery in patients with acute myocardial infarction. We investigated the effect of verapamil on the restoration of myocardial perfusion and functional recovery in patients with angiographic no-reflow after PCI. Methods99mTc tetrofosmin single photon emission computed tomographic (SPECT) imaging was performed (before, immediately after and 1 month after PCI) in 101 consecutive patients with acute myocardial infarction. The defect score was calculated as the sum of perfusion defect in a 13-segment model (scores of 3, complete defect to 0, normal perfusion). The asynergic score, defined as the number of asynergic segments, was assessed by echocardiography before and 1 month later. Multiple logistic regression analysis was performed to elucidate the effect of verapamil administration. ResultsOf 101 patients, 32 (31%) had angiographic no-reflow and were divided into two groups: 18 patients with verapamil (group 1) and 14 patients without verapamil (group 2). Sixty-nine patients had TIMI grade 3 reflow after PCI (group 3). The change in the defect score 1 month after PCI in group 1 was significantly larger than that in group 2 (P=0.003). The asynergic score improved more at 1 month in group 1 compared to that in group 2 (P=0.007). Moreover, logistic regression analysis revealed that TIMI grade reflow ≤2 after PCI (P=0.04, OR=5.51), the defect score before PCI (P=0.03, OR=1.15), the asynergic score before PCI (P=0.01, OR=0.64) and the administration of verapamil (P=0.002, OR=22.4) were independently associated with successful myocardial reperfusion immediately after PCI. ConclusionsIntracoronary verapamil restored myocardial perfusion in patients with angiographic no-reflow after PCI and lead to better functional recovery after acute myocardial infarction.

Oxygen utilization, carbon dioxide elimination and ventilation during recovery from supine bicycle exercise 6 to 8 weeks after acute myocardial infarction

The pattern of oxygen (O2) consumption (VO2), carbon dioxide (CO2) production (VCO2), ventilatory and metabolic responses during and in recovery from supine bicycle exercise was examined in 18 patients with recent myocardial infarction. An increase in VO2 with increasing work load was accomplished by proportional increases in both cardiac output and the arteriovenous O2 difference. During recovery, however, the arteriovenous O2 difference rapidly decreased below levels at rest, whereas VO2 and cardiac output remained elevated, indicating that VO2 during recovery further depended on relatively high cardiac output. The ratio of VCO2 to VO2 further increased after exercise, suggesting that such cardiac output contributed to the remaining high CO2 flow to the lung and therefore enhanced ventilation. Increased arterial catecholamines during exercise remained elevated for the first 5 minutes of recovery. Arterial lactate during this period continued to increase and resulted in profound metabolic acidosis, causing alveolar hyperventilation after exercise. These results suggest that during recovery from exercise, cardiopulmonary responses remain enhanced because of continuing high cardiac output, resulting in subsequent high CO2 flow to the lung and metabolic acidosis, and that this may be associated with profound fatigue or dyspnea after exercise.

Effects of left ventricular diastolic dysfunction on exercise capacity three to six weeks after acute myocardial infarction in men

To examine the effects of left ventricular (LV) diastolic dysfunction on exercise capacity, hemodynamic and radionuclide responses were measured at rest and during exercise in 50 patients with recent myocardial infarction. The ratio of an increase in pulmonary arterial wedge pressure (PAWP) to an increase in LV end-diastolic volume (EDV) from rest to peak exercise (delta PAWP/delta EDV) was used as an index of LV diastolic function, delta PAWP/delta EDV had modest and negative correlations with peak oxygen consumption (VO2), cardiac output, and stroke volume in all patients. Among patients with peak VO2 > or = 20 ml/min/kg (group I, n = 24) and those with peak VO2 < 20 ml/min/kg (group II, n = 26), there were no differences between the 2 groups with regard to resting LV ejection fraction, EDV, PAWP, cardiac output, and stroke volume. Although there was no significant difference in LV ejection fraction at peak exercise, group II had significantly reduced EDV, increased PAWP, and decreased cardiac output and stroke volume than those in group I. As a result, delta PAWP/delta EDV was significantly higher in group II. These results suggest that LV diastolic dysfunction has a key role in determining exercise capacity in patients with reduced exercise capacity after recent myocardial infarction.

Right ventricular ejection fraction during exercise in patients with recent myocardial infarction: Effect of the interventricular septum

To investigate the effect of interventricular septum (IVS) on right ventricular function during exercise, radionuclide angiocardiography was performed in 50 patients with recent myocardial infarction. Twenty-five patients had involvement of IVS according to thallium uptake in IVS (group I), and 25 patients were free of IVS involvement (group II). Although there was no statistical difference between the two groups in right ventricular ejection fraction (EF) at rest (45% +/- 10% vs 48% +/- 8%), patients in group I had significantly lower left ventricular (LV) EF (40% +/- 11% vs 53% +/- 11%, p < 0.01) and larger LV end-diastolic volume (129 +/- 46 vs 106 +/- 31 ml, p < 0.05) than those in group II. All parameters increased significantly during exercise in both groups, but patients in group I had significantly lower exercise right ventricular EF (50% +/- 10% vs 56% +/- 9%, p < 0.05), LVEF (44% +/- 11% vs 56% +/- 13%, p < 0.01), and larger LV end-diastolic volume (155 +/- 44 vs 129 +/- 37 ml, p < 0.05) than those of group II. Significant correlations were observed between right ventricular EF and LV end-diastolic volume at rest and during exercise (r = -0.48, p < 0.05, and r = -0.68, p < 0.01, respectively) in group I, but right ventricular EF correlated with LVEF only at peak exercise (r = 0.65, p < 0.01). In contrast, right ventricular EF did not correlate with any variables at rest or during exercise in group II.(ABSTRACT TRUNCATED AT 250 WORDS)