ALTERATIONS OF MYOCARDIAL BLOOD FLOW IN PATIENTS WITH CARDIOMYOPATHY FOLLOWING LONG-TERM LVAD SUPPORT
Michael J. EppingerDavid M. RaffelJames R. CorbettKeith D. AaronsonClaire S. DuvernoySusan WrightFrancis D. Pagani
0
Citation
0
Reference
10
Related Paper
Abstract:
Background: Circulatory support with an implantable LVAD has been shown to normalize perfusion pressure, reduce left ventricular (LV) wall stress, and improve LV structure and myocyte function, in some cases enabling LVAD explant. Improvement in myocardial blood flow (MBF) as a consequence of improved hemodynamics may contribute to the subsequent beneficial changes observed in myocyte structure and function following long-term LVAD implant. Methods: Positron emission tomography (PET) with [13N]ammonia imaging was performed in 5 patients with cardiomyopathy (all male, median age 57, 2 ischemic, 3 idiopathic) at the time of evaluation for LVAD implant (HeartMate® LVAD; Thermo Cardiosystems, Inc) and subsequently at 4–6 weeks following implant. In three of the patients, pre and postoperative hemodynamic and exercise testing were available. Results: Following LVAD implant, there was a significant improvement in hemodynamics and peak exercise oxygen consumption (mean improvements in cardiac index 3.5 vs. 1.8 1/min/m2, pulmonary capillary wedge pressure 9 vs. 25 mm Hg, maximum exercise oxygen consumption 17 vs. 13 ml/kg/min, p<.05 for each). In 3 of 5 patients, MBF increased an average of 101%. 2 patients demonstrated no change in MBF. Conclusions: Despite restoration of normal hemodynamics with significant LV unloading, these data suggest that alterations in MBF are variable and may be related to coronary autoregulation and myocardial oxygen demand. These data have implications for potential LV recovery following long-term LVAD support.Keywords:
Pulmonary wedge pressure
Coronary flow reserve
Destination therapy
Pulsatile flow
Pulmonary wedge pressure
Bridge to transplantation
Artificial heart
Cite
Citations (1)
Coronary flow reserve
Dobutamine
Fractional Flow Reserve
Circumflex
Coronary arteries
Cite
Citations (57)
Pulmonary venous wedge pressure closely reflects the pulmonary arterial mean pressure. Pulmonary arterial wedge pressure is not significantly different from the left atrial mean pressure. Neither the former nor the latter is an approximation of the pulmonary capillary pressure.
Pulmonary wedge pressure
Pulmonary arterial pressure
Wedge (geometry)
Left atrial pressure
Venous pressure
Cite
Citations (20)
With a view to investigating the Peripheral Circulatory Insufficiency particularly in the field of surgical operations, the author has under-taken a circulatory analysis by means of modification of Wezler's methods which is among those used in connection with the physical methods for circulatory analysis. Two electric manometers, of the identical capacity, were attached to the carotic artery and the crural artery so as to record their pulse waves, from which were calculated the circulatory values by the Wezler formula. A total of 96 cases were subject to the investigation were examined before and after a surgical operation to observe the Circulatory Insufficiency throughout. The findings before the operations indicated 42% was accounted for the circulatory regulation of " Anspannungs " and in terms of diseases, the stomach cancer and cardia cancer cases claimed more than half in this category and those of the esophagus cancer nearly the half. The tachycardia cases at a resting period before the operation increased by 20%. In-stances of low cardiac output were noted in the patients of the cancer of digestive organs. The findings after the operations indicated that the majority of "Anspannungs" circulatory regulation took place right after the operations. A better circulatory condition after the operation was observed with a general anesthesia rather than with a spinal anesthesia. The fact that blood transfusion during the operation had a beneficial effect on the post operative low cardiac output behavior testified to the existence of a relationship between the two. Changes in the circulatory regulation owing to an operation were of the normal type but, depending on the nature of cases involved, there had appeared the patients who required the "Anspannungs " regulation immediately after their operations, only returning to the normal with the lapsing of time. It was also made clear that in such cases where the cardiac output was low both before and after the operations, the general tendency was to incur a circulatory insufficiency. In determining whether a case of low cardiac output occurred or not, indications were employed that before an operation the pulse pressure count was under 40 mmHg and after an operation the pulse pressure count was under 40 mmHg and the heart beat count was either over 100 or under 70. In the pre-operation study, 75% of the cases and post-operation study, 100 of the cases falling under the former category were diagnosed as being the low cardiac output. As the conclusions, it has been establised that though is a great deal of the "Anspannungs" circulatory regulation this is by no means a contraindication for any type of circulatory regulationin in surgical operation. A general anesthesia is preferred in a surgical operation, a blood transfusion during an operation had a beneficial effect on the subsequent low cardiac output, the use of some cardiotonic is recommended. On the determination of low cardiac output by means of the pulse pressure count is available especially immediately after the operation. Finally, it is considered that Wezler modification method is a useful tool in the precaution of the Peripheral Circulatory Insufficiency to be encountered in surgery.
Circulatory collapse
CIRCULATORY FAILURE
Cite
Citations (0)
Introduction: Although coronary flow reserve (CFR) has been the only physiological way to evaluate the coronary microvascular (MV) function until recently, hyperemic MV resistance (hMR) have been developed as a newer modality measuring directly coronary MV function. Discordance between CFR and hMR may reflect various coronary hemodynamic situations. Hypothesis: Simultaneous measurement of CFR/hMR in pts without coronary obstruction could provide us deeper appreciation of hemodynamic functional alterations in coronary microvasculature. Methods: In 44 pts without coronary stenosis (diameter stenosis >50%), CFR and hMR were measured utilizing a dual sensor (Doppler velocity and pressure)-equipped guidewire. To evaluate coronary MV hemodynamics, pts were categorized into four CFR/hMR quadrants using a cutoff values of CFR≥2.0 and hMR<1.7 (median value of all study subjects) (Figure). Results: Discordance results between CFR/hMR was present in 39% of patients (17 of 44), with CFR≥2.0 and hMR≥1.7 in 30% (13 of 44) and CFR<2.0 and hMR<1.7 in 9% (4 of 44). There were significantly negative correlation between hMR and hyperemic average peak velocity (APV) (r=-0.73, p<0.0001), CFR and baseline APV (r=-0.66, p<0.001) despite no correlation between CFR and hyperemic APV (r=0.25, p=0.1). Baseline APV and hyperemic APV were significantly different among these groups (baseline APV; group 2 vs. group 3, 12.0±5.7 vs. 30.5±7.2, p=0.02, group 2 vs. group 4, 12.0±5.7 vs. 21.3±8.5, p=0.002, hyperemic APV; group 1 vs. group 4; 51.2±10.4 vs. 28.7±10.2, p<0.0001, group 1 vs. group 2, 51.2±10.4 vs. 32.5±13.6, p=0.03). Four CFR/hMR quadrants thus represent 4 different types of coronary blood flow-perfusion pressure relationship (Figure). Conclusions: In pts without coronary obstruction, CFR was related to coronary autoregulation state and hMR to hyperemic state. Simultaneous CFR/hMR measurement might provide new physiological insight about coronary MV hemodynamics.
Coronary flow reserve
Fractional Flow Reserve
Coronary circulation
Cite
Citations (0)
Evidence suggests a major role for von Willebrand factor (vWF) in left ventricular assist device (LVAD)-associated bleeding. However, the mechanisms of vWF degradation during LVAD support are not well understood. We developed: (i) a simple and inexpensive vortexer model; and (ii) a translational LVAD mock circulatory loop to perform preclinical investigations of LVAD-associated vWF degradation. Whole blood was obtained from LVAD patients (n = 8) and normal humans (n = 15). Experimental groups included: (i) blood from continuous-flow LVAD patients (baseline vs. post-LVAD, n = 8); (ii) blood from normal humans (baseline vs. 4 h in vitro laboratory vortexer, ∼ 2400 rpm, shear stress ∼175 dyne/cm(2) , n = 8); and (iii) blood from normal humans (baseline vs. 12 h HeartMate II mock circulatory loop, 10 000 rpm, n = 7). vWF multimers and degradation fragments were characterized with electrophoresis and immunoblotting. Blood from LVAD patients, blood exposed to in vitro supraphysiologic shear stress, and blood circulated through an LVAD mock circulatory loop demonstrated a similar profile of decreased large vWF multimers and increased vWF degradation fragments. A laboratory vortexer and an LVAD mock circulatory loop reproduced the pathologic degradation of vWF that occurs during LVAD support. Both models are appropriate for preclinical studies of LVAD-associated vWF degradation.
Cite
Citations (28)
Pulmonary wedge pressure
Cardiac index
Cite
Citations (0)
Pulmonary wedge pressure
Wedge (geometry)
Cite
Citations (27)
A 46-year-old man with a continuous flow left ventricular-assist device implanted as destination therapy 2 years ago (CF-LVAD; HeartMate II, Thoratec Corporation, Pleasanton, CA, USA) presented with syncope, low flow device alarms, and several brief device stoppage events. The patient had been off anticoagulation (warfarin, International Normalized Ratio goal of 2.0–2.5) and anti-platelet agent (aspirin, 81 mg daily) for 5 months due to a large …
Cite
Citations (0)
Pulmonary wedge pressure
Preload
Ventricular pressure
Wedge (geometry)
Cite
Citations (3)