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T A Gasior

Publications and source records attributed to T A Gasior.

25 records · Page 2Linked to original sources
PubMedDate not supplied

Quantitation of right ventricular shape changes after left ventricular assist device implantation.

Complex effects of left (LV) and right ventricular (RV) interaction account for changes in RV function during LV assist device (LVAD) support. It has been hypothesized that changes in RV cross-sectional shape (RVS) may be a contributing factor in the development of RV dysfunction during LVAD support. To test the hypothesis that the RVS would become more circular as a result of septal shift during LVAD support, 13 patients were studied before and after LVAD implantation. The shape of the RV was quantified using a shape factor (SF) that was equal to (4 x pi x area)/P2, where P is the perimeter of RVS. The RV area and perimeter were measured from digitized images of the RV obtained by transesophageal echocardiography in patients before and after LVAD implantation. The group SF increased considerably after LVAD (SFpre = 0.78 +/- 0.12 versus SFpost = 0.88 +/- 0.07, p < 0.05). Patients were divided into three groups: 1) patients whose RV exhibited a low SF pre-LVAD that increased significantly, 2) those with a moderate SF pre-LVAD that increased slightly, and 3) those who had high pre-LVAD SF (< 0.90) that did not change. The decompression of the LV caused by LVAD implantation results in a shift of the septum from right to left, increasing SF. This increase is more pronounced in some patients. Quantitation of the degree of RV SF change may help predict the development of RV failure during LVAD support.

Adult↗
PubMedDate not supplied

Differential regional function of the right ventricle during the use of a left ventricular assist device.

The use of a left ventricular assist device (LVAD) as a bridge to transplant is associated with a 52% incidence of RV failure requiring additional inotropic or mechanical support (RVAD). This study evaluated the differential performance of the RV free wall and septum to identify the need for additional RV support. Cross-sectional views of the RV were obtained immediately before, and 1 hr after, Novacor LVAS implantation in 12 consecutive patients using transesophageal echocardiography. Each image was divided into a free wall portion (FW) and a septal portion (SP) by grids drawn from the center of gravity of the end-diastolic endocardial outline to the junction between the FW and the SP. Percentage change between preimplant and postimplant for RV ejection fraction (RVEF), fractional area change for the FW (FAC-FW) and the SP (FAC-SP), and fractional shortening of the FW to SP distance (F-S) is reported for patients based upon the need for RV support: minimal (Group 1), maximal (Group 2). After LVAS implantation, patients showed a reduction in SP fractional area change. However, this reduction was most pronounced in Group 2. The degree of SP impairment may explain the mechanism of RV failure in patients on an LVAD.

Adolescent↗
PubMedDate not supplied

Dynamic biventricular response to alterations in preload in patients undergoing left ventricular device implantation.

Ventricular interdependence is important for the successful use of a left ventricular assist device (LVAD) because the filling of the device depends on right ventricular (RV) function as well as the interactions between the ventricles. The pulmonary arterial (PAP) and systemic arterial (AP) response to inferior vena caval (IVC) occlusion before and after insertion of an LVAD in 15 patients was used to "dissect out" the determinants of these interactions. PAP and AP were recorded during each IVC occlusion and peak systolic values calculated for each beat. Linear regression analysis was used to calculate the slope (k) between peak systolic AP values and peak systolic PAP values. k, a measure of preload responsiveness of the heart, is predominantly linear. k is relatively "flat" in selected LV failure patients pre-LVAD but increases significantly (P < 0.001) after LVAD (0.67 +/- 0.55 vs. 2.71 +/- 1.39). The increase in this parameter after LVAD suggests that the loss of RV-to-LV ventricular interdependence in patients with congestive heart failure appears to recover somewhat once an LVAD is inserted.

Adolescent↗
PubMedDate not supplied

Estimation of left ventricular function in patients with a left ventricular assist device.

Patients with profound left ventricular (LV) dysfunction supported by a left ventricular assist device (LVAD) may have recovery of LV function, but current methods for assessing this are difficult or not readily available. A new method to estimate LV performance was tested in 6 patients on LVAD (age, 47 +/- 12 years). Simultaneous measures of LV cross-sectional area (substitute for volume) using transesophageal echocardiographic automated border detection and femoral arterial pressure (substitute for LV ejection pressure) were recorded during brief periods on and off LVAD. During the LVAD off period, femoral arterial pressure and LV area signals were combined on-line to generate arterial pressure-LV area loops. The slope of the linear regression line connecting the end systolic points generated during LV filling after LVAD off was used as an estimate of end systolic elastance denoted by Ees. The average Ees was 3.8 +/- 3.1 mmHg/cm2. These values are significantly lower than those of 13 control patients (22.3 +/- 15.4 mmHg/cm2). This method of estimating Ees may be clinically useful in assessing LV recovery in patients on LVAD after extended support.

Adult↗
PubMedDate not supplied

A clinical trial comparing University of Wisconsin solution and cold cardioplegic solution with load-independent mechanical parameters.

To evaluate the efficacy of University of Wisconsin solution for clinical heart transplantation, load-independent parameters were used to assess left ventricular function after transplantation. Donor hearts were arrested with and stored in buffered cold cardioplegic solution for control (n = 5) and University of Wisconsin solution for the experimental group (n = 5). Orthotopic transplantations were performed in a routine manner. Mean donor age (cardioplegic solution, 28 +/- 5.2 years; University of Wisconsin solution, 28 +/- 5.1 years) and ischemic times (cardioplegic solution, 181 +/- 27 minutes; University of Wisconsin solution, 224 +/- 23 minutes) were similar. Two hours after reperfusion of the heart, transesophageal echocardiography was used to image the left ventricle at the mid-papillary muscle level, and a high-fidelity catheter-tipped manometer was placed in the left ventricle to record left ventricular pressure simultaneously. These images were digitized during apneic baseline conditions and during an acute reduction in preload from inferior vena caval occlusion. The left ventricular cross-sectional areas were measured and matched with left ventricular pressure from the catheter-tipped manometer to reveal pressure-area relationships. The baseline parameters fractional area change and stroke force were calculated. End-systolic elastance, the slope of end-systolic pressure-area relationship and preload recruitable stroke force, the slope of stroke force versus end-diastolic area were calculated from the inferior vena cava occlusion measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMedDate not supplied

Assessment of timing right ventricular assist device withdrawal using left ventricular assist device filling characteristics.

Right ventricular assist devices (RVAD) are often needed on a short term basis in patients who develop RV failure after left ventricular assist device (LVAD) implantation. The purpose of this study was to use LVAD filling characteristics to help determine the timing for weaning a patient from RVAD support. Eleven patients (age 50 years +/- 15) supported with an LVAD (Novacor) and an RVAD (Biomedicus or ABIOMED) were studied. Eight patients (RV recovery group) were studied before RVAD removal and all were successfully weaned from RVAD support. Five patients (RV failure group) were studied at the time of RVAD placement to determine baseline characteristics of RV failure. Simultaneous measures of LVAD volume and routine hemodynamics were recorded during periods of high and low RVAD flow. The LVAD filling was assessed as the first derivative of LVAD volume and the mean filling rate for each cardiac cycle was calculated and averaged over 10 sec periods at both RVAD flows. The mean pump rate corrected filling rates did not change in the RV recovery group (89 +/- 13 vs. 87 +/- 8 ml/beat) and significantly decreased in the RV failure group (84 +/- 19 vs. 62 +/- 22 ml/ beat) (p < 0.001) with decreasing RVAD flow. These data suggest that LVAD filling rates may be used to assess RV systolic function and the proper timing of RVAD removal in selected patients.

Adult↗