Mehmet Kabukçu

Effects of Different Dialysis Modalities on Cardiac Autonomic Dysfunctions in End-Stage Renal Disease Patients: One Year Prospective Study

Cardiac autonomic dysfunction (CAD) is a common problem in patients with end‐stage renal disease (ESRD) and may contribute to the risk of cardiac mortality. Long‐term effects of dialysis modalities on CAD in ESRD patients are not clear. In this one‐year prospective study, we studied the effects of different dialysis modalities on CAD in ESRD patients. The study consisted of 20 ESRD patients who had the indications for initiating dialysis therapy (13 hemodialysis and 7 CAPD patients) and 15 healthy controls (M/F: 5/10; age 30 ± 4). In all the subjects, first at the beginning of study (in patient groups just before initiating dialysis therapy) and then after 12 months, we studied 24 hours ECG‐Holter monitoring and heart rate variability parameters (time and frequency domain analysis parameters; SDNN: standard deviations of nn intervals, rMSSD: square root of the median of standard deviation, HRVI: heart rate variability index, LF/HF: low frequency/high frequency). In ESRD patients, before dialysis therapy, all the parameters of time domain analysis were significantly lower compared to control group (p = 0.001). In patient groups, after dialysis therapy (on the 12th month), significant improvement was observed in time domain analysis parameters (p = 0.001). When dialysis modalities were compared, the increase in the time domain analysis parameters was significantly greater in the CAPD group compared to hemodialysis (HD) group. Our findings suggest that CAD is frequent in ESRD patients, a dialysis therapy of 12 months can cause significant improvement on CAD and the ameliorative effect of CAPD is better than HD.

Comparison of the three different formulas for Doppler estimation of pulmonary artery systolic pressure.

Noninvasive pulmonary artery systolic pressure (PASP) is calculated by summing the right ventricular systolic pressure obtained from Doppler velocity of regurgitant flow through the tricuspid valve and the right atrial (RA) pressure. The RA pressure is generally assumed from different formulas. An accurate RA pressure estimation will add precision to PASP calculation. One of the methods to estimate RA pressure is the inferior vena cava collapsibility index (IVCCI) . In 45 patients referred for right heart catheteri zation, the authors tested a formula for the calculation of PASP based on the estimation of RA pressure from IVCCI and compared this method with two other formulas. The first method (method 1) assumed a constant RA pressure of 10 mm Hg irre spective of right ventricular pressure. The formula used was Doppler gradient + 10 (mm Hg). In the second method (method 2), a clinical estimate of RV pressure was made from the formula: right ventricular-right atrial Doppler gradient x 1.1 + 14. In the third method (method 3), the patients were classified into three groups on the basis of IVCCI: group A, IVCCI greater than 45%; group B, IVCCI between 35% and 45%; and group C, IVCCI less than 35%. The formula used was Doppler gradient + 6, 9, or 16 mm Hg in the presence of normal (group A), moderately reduced (group B), or markedly reduced (group 3) IVCCI. A good correlation between Doppler and catheter measurements of PASP was found for methods 1, 2, and 3, respectively (r=0.8933, SEE=6.4, r=0.8921, SEE=7.0, and r=0.8989, SEE=6.7). Correlation between invasive and noninvasive PASP was similar with the three methods, but correlation in method 2 was less satisfactory than with the other two methods. The mean difference between Doppler-derived and hemodynamic PASP was also high in method 2. In conclusion, the result of this study validates a relatively new, simple echo-Doppler formula for Doppler estimation of PASP based on a noninvasive evaluation of RA pressure through the IVCCI. However, this method is not better than the traditional method 1 for noninvasive PASP estimation.

Percutaneous Balloon Valvuloplasty for Severe Mitral Stenosis in Pregnancy Four Case Reports

Four pregnant women with mitral stenosis who did not respond to medical therapy underwent successful percutaneous balloon valvuloplasty with complete resolution of their symptoms. Their clinical features and echocardial and hemodynamic data are presented. The procedures and the remainder of their pregnancy were uncomplicated. Percutaneous balloon valvuloplasty of the mitral valve is a safe and effective alternative to surgical therapy if medical management is unsuccessful.

Is There Any Association Between Dissection After Successful Percutaneous Transluminal Coronary Angioplasty and Late Restenosis? An Angiographic Study

Restenosis continues to be the most important limitation of percutaneous transluminal coronary angioplasty (PTCA). Many clinical, angiographic, and procedural variables are thought to be related to the development of restenosis. This study was aimed at investi gating the effects of no dissection, minor dissections, and major dissections on the long- term outcome of lesions after successful PTCA. The study group comprised 91 patients with 100 lesions who underwent successful PTCA and in whom follow-up coronary angiography was performed at 8.8 ± 7.2 (two to twenty-three) months after dilation. Dissections were classified according to the National Heart, Lung, and Blood Institute criteria. Restenosis was defined as more than 50% stenosis at follow-up angiography. Restenosis rates were found to be 22% in the no-dissection group (10 restenoses in 46 patients), 27% in the minor dissection group (11 restenoses in 40 patients), and 36% in the major dissection group (5 restenoses in 14 patients). The authors applied corrected Yates Chi-square test and no difference was observed in the restenosis rate between the group without any dissections and that with minor dissections (P > 0.05). However, a statistically significant difference was observed in the restenosis rate between the major dissection group and the other two groups (P < 0.05). The authors conclude that the occurrence of major dissections after successful PTCA may adversely affect the long-term outcome and may increase the restenosis rate.

Left atrial function as a predictor of haemodynamic response in patients with mitral stenosis: a dobutamine stress echocardiographic study.

Objective—The mechanisms of the different haemodynamic and clinical responses to dobutamine infusion in mitral stenosis (MS) are not clearly established. The aim of this study was to evaluate the relation between left atrial (LA) function and haemodynamic response in patiens with MS during dobutamine infusion. Methods and results — Forty-two consecutive moderately symptomatic patients (33 women, 9 men; mean age 46±9, range from 26 to 66), NewYork Heart Association (NYHA) class II with MS (mean mitral valve area 1.7±0.1cm2) were evaluated with dobutamine stress echocardiography. Haemodynamic measurements were obtained at rest and during peak dobutamine infusion. LA fractional shortening at rest was used as an index of global LA function. Group I consisting of patients with significantly elevated pulmonary artery pressure (>60 mm Hg) and mean transmitral gradient (>15 mm Hg) at peak dobutamine infusion were defined as haemodynamically serious MS. Group II consisted of the remaining 30 patients whose haemodynamic data were below these levels.While baseline haemodynamic parameters and mitral valve characteristics were not different between the two groups, LA fractional shortening was significantly lower (18.9±2.8 vs. 32.3±5.1%, p<0.0001) and left atrial dimension was significantly larger in group I (49.7±2.3mm vs 43.6±5.3 mm, p<0.0001). Left atrial fractional shortening was negatively correlated with the increase in mean transmitral gradient (r:-0.58, p<0.01). When the patients were divided using a LA fractional shortening level of 25% as the cut-off point, we observed that the patients with low LA fractional shortening had a greater increase in mean transmitral gradient (7.3±3.1 mm Hg vs. 4.6±1.4 mm Hg), p = 0.005) and pulmonary artery pressure (22.4±3.5 mm Hg vs. 16.1±8.5 mm Hg, p = 0.001) compared to the patients with high LA fractional shortening. Based on these haemodynamic results, management was changed in 12 patients (28%): 5 underwent percutaneous mitral balloon commissurotomy and 7 received intensive medical treatment. Conclusions—The present study demonstrates that haemodynamic response during dobutamine stress echocardiography correlates with LA fractional shortening in patients with MS. The evaluation of left atrial function at rest in patients with ambiguous symptoms and mild mitral stenosis may be useful in clinical decision making. Atrial dysfunction at rest may predict the haemodynamic response during stress echo in these patients.

Does increased lipoprotein (a) impair the effectiveness of thrombolysis with streptokinase

Although lipoprotein (a) [Lp(a)] has been shown to interfere with thrombolysis in vitro, its effects on thrombolytic therapy in patients with acute myocardial infarction (MI) are not clear. The authors evaluated 32 male patients ages thirty-five to seventy-five (mean fifty-two ±ten) with the diagnosis of acute MI who underwent thrombolytic therapy with 1,500,000 units of intravenous streptokinase. All patients underwent coronary angio graphy within seven days of the infarction from which the thrombolysis in myocardial infarction (TIMI) flow grades of the infarct-related artery, coronary scores, and ejection fraction were determined. Anterior MI was found in 19 patients (59.4%), inferior MI in 12 (37.5%), and posterolateral MI in 1 patient (3.1%). They found that 6 patients (18.8%) had TIMI flow 0 to 1, and 26 patients (81.2%) had TIMI flow grade 2 or 3. The Lp(a) levels ranged from 0.1 to 60 mg/dL with a mean of 8.6 ±17 mg/dL. Eight (25%) of the patients had Lp(a) levels above 30 mg/dL. The TIMI flow rates were not found to be lower in patients with high Lp(a) levels (P > 0.05), and there was no significant corre lation between the TIMI flow rates and the Lp(a) levels (r=0.28). There was a good correlation between coronary scores and Lp(a) levels (r=0.87). They conclude that although there is a good correlation between the extent of coronary atherosclerosis and Lp(a) levels, Lp(a) is not a strong predictor of the outcome of thrombolytic therapy.