Pulsatility and flow patterns across macro- and microcirculatory arteries of continuous-flow left ventricular assist device patients

BACKGROUND

Reduced arterial pulsatility in continuous-flow left ventricular assist devices (CF-LVAD) patients has been implicated in clinical complications. Consequently, recent improvements in clinical outcomes have been attributed to the "artificial pulse" technology inherent to the HeartMate3 (HM3) LVAD. However, the effect of the "artificial pulse" on arterial flow, transmission of pulsatility into the microcirculation and its association with LVAD pump parameters is not known.

METHODS

The local flow oscillation (pulsatility index, PI) of common carotid arteries (CCAs), middle cerebral arteries (MCAs) and central retinal arteries (CRAs-representing the microcirculation) were quantified by 2D-aligned, angle-corrected Doppler ultrasound in 148 participants: healthy controls, n = 32; heart failure (HF), n = 43; HeartMate II (HMII), n = 32; HM3, n = 41.

RESULTS

In HM3 patients, 2D-Doppler PI in beats with "artificial pulse" and beats with "continuous-flow" was similar to that of HMII patients across the macro- and microcirculation. Additionally, peak systolic velocity did not differ between HM3 and HMII patients. Transmission of PI into the microcirculation was higher in both HM3 (during the beats with "artificial pulse") and in HMII patients compared with HF patients. LVAD pump speed was inversely associated with microvascular PI in HMII and HM3 (HMII, r2 = 0.51, p < 0.0001; HM3 "continuous-flow," r2 = 0.32, p = 0.0009; HM3 "artificial pulse," r2 = 0.23, p = 0.007), while LVAD pump PI was only associated with microcirculatory PI in HMII patients.

CONCLUSIONS

The "artificial pulse" of the HM3 is detectable in the macro- and microcirculation but without creating a significant alteration in PI compared with HMII patients. Increased transmission of pulsatility and the association between pump speed and PI in the microcirculation indicate that the future clinical care of HM3 patients may involve individualized pump settings according to the microcirculatory PI in specific end-organs.

Major bleeding during HeartMate II support

OBJECTIVES

The aim of this study was to characterize a single-center experience of major bleeding complications during HeartMate II (HMII) (Thoratec Corp., Pleasanton, California) left ventricular assist device support, with focus on the subtypes and temporal patterns of post-operative bleeding.

BACKGROUND

Bleeding complications are the most common post-operative adverse events after HMII implantation. The timing of bleeding events, relationship to coagulation status, and effect on post-operative survival are incompletely understood.

METHODS

From October 2004 to June 2010, 139 HMII recipients at the Cleveland Clinic received 145 devices as a bridge to transplant or destination therapy for advanced heart failure. Major bleeding was defined using Interagency Registry for Mechanically Assisted Circulatory Support criteria, with an additional category created to maximize sensitivity for events. Pre-operative variables, coagulation status, and bleeding recurrence were assessed for correlation to primary events using modulated renewal within a multivariable analysis.

RESULTS

The cumulative occurrence of major bleeding was 58% during 171 patient-years of follow-up. There were 1.14 major bleeds per patient-year, with 44% occurring as repeat bleeding events. A first bleed did not predict subsequent bleeding. The greatest risk of bleeding was noted within 2 weeks post-implantation. The international normalized ratio profile correlated poorly with the risk of bleeding. Bleeding early after surgery was associated with reduced survival while on HMII support.

CONCLUSIONS

The risk of bleeding peaks early after HMII implantation. Bleeding of thoracic and gastrointestinal sources dominates these events, although many patients undergo transfusions for anemia without an apparent source of hemolysis or bleeding.

Preoperative diagnostic workup before antireflux surgery: an evidence and experience-based consensus of the Esophageal Diagnostic Advisory Panel

BACKGROUND

Gastroesophageal reflux disease (GERD) is a very prevalent disorder. Medical therapy improves symptoms in some but not all patients. Antireflux surgery is an excellent option for patients with persistent symptoms such as regurgitation, as well as for those with complete symptomatic resolution on acid-suppressive therapy. However, proper patient selection is critical to achieve excellent outcomes.

STUDY DESIGN

A panel of experts was assembled to review data and personal experience with regard to appropriate preoperative evaluation for antireflux surgery and to construct an evidence and experience-based consensus that has practical application.

RESULTS

The presence of reflux symptoms alone is not sufficient to support a diagnosis of GERD before antireflux surgery. Esophageal objective testing is required to physiologically and anatomically evaluate the presence and severity of GERD in all patients being considered for surgical intervention. It is critical to document the presence of abnormal distal esophageal acid exposure, especially when antireflux surgery is considered, and reflux-related symptoms should be severe enough to outweigh the potential side effects of fundoplication. Each testing modality has a specific role in the diagnosis and workup of GERD, and no single test alone can provide the entire clinical picture. Results of testing are combined to document the presence and extent of the disease and assist in planning the operative approach.

CONCLUSIONS

Currently, upper endoscopy, barium esophagram, pH testing, and manometry are required for preoperative workup for antireflux surgery. Additional studies with long-term follow-up are required to evaluate the diagnostic and therapeutic benefit of new technologies, such as oropharyngeal pH testing, multichannel intraluminal impedance, and hypopharyngeal multichannel intraluminal impedance, in the context of patient selection for antireflux surgery.