Effects of the 14F hemopump on coronary hemodynamics in patients undergoing high-risk coronary angioplasty

Hemodynamic Properties of the Hemopump HP14

Background

The Hemopump HP14 is a catheter-mounted, transvalvular, left ventricular assist device intended for femoral percutaneous insertion. The pump was developed for patients with postoperative or postinterventional low cardiac output and for CABG surgery on the beating heart. Little is known about the effect of afterload and hematocrit on the pump performance.

Methods

The influence of hematocrit and afterload on the pump flow was tested using an in vitro model filled with heparinized bovine blood. Regression analysis of the pump flow with respect to three hematocrit values (20%, 30%, 40%) and ten afterload levels (30 mmHg-120 mmHg in 10 mmHg increments) was performed for all pump speed levels (n = 7).

Results

At all pump speed levels reduction of afterload and hematocrit were significant predictors for increasing pump flow (p<0.001). For hematocrit values between 40% and 20% and highest pump speed, mean pump flow at lowest afterload ranged between 2.34 and 2.53 L/min; and at highest afterload between 1.31 and 1.53 L/min. For speed level 1, afterload of 120 mmHg and hematocrit of 40% there was a maximal retrograde flow of 230 ± 35 ml/min.

Conclusions

Pump performance is significantly improved by both afterload and hematocrit reduction. In the weaning phase and during the removal of the device, the pump should run at a speed level of at least three to prevent retrograde flow in the pump. Estimates for pump flow in vivo can be extrapolated from our diagrams. Our results show that the Hemopump HP14 is a valuable alternative to intra-aortic balloon counterpulsation.

Left ventricular unloading and concomitant total cardiac output increase by the use of percutaneous impella recover LP 2.5 assist device during high-risk coronary intervention

A number of techniques have been proposed for circulatory support during high-risk percutaneous coronary interventions (PCI), but no single approach has achieved wide acceptance so far. We report on a patient with severe left ventricular (LV) impairment who underwent a PCI with the use of a new left ventricular assist device, the Impella Recover LP 2.5 system. The effects on global cardiac output were determined by thermodilution (TD) and LV pressure-volume loops obtained by conductance catheter. The activation of the pump resulted in a rapid and sustained unloading effect of the LV. At the same time, the continuous expulsion of blood into ascending aorta throughout the cardiac cycle produced by the pump resulted in an increase of systemic overall CO, measured by the TD technique, of 1.43 L/min. The procedure was uncomplicated and the patient remained uneventful at follow-up. Our single experience gives new input for future trials to assess the effect of the Impella Recover LP 2.5 assist device on outcome in this subset of patients.

Successful high-risk coronary angioplasty in a patient with cardiogenic shock under circulatory assist with a 16F axial flow pump

We report the case of a 75-year-old patient who suffered from subacute myocardial infarction and severely impaired left ventricular ejection fraction (EF: 17%). Using a novel 16F left ventricular assist device we performed an angioplasty of the right coronary artery, and of the left anterior descending artery. As a result of the circulatory support the patient recovered from cardiogenic shock within 8 hr. At a pump speed of 45,000 rpm the axial flow pump generated flow rates up to 3.3 l/min. The 16F pump cannula was removed using local compression. The EF was 51% at 30-day follow-up examination.

Clinical introduction of the Tandemheart, a percutaneous left ventricular assist device, for circulatory support during high-risk percutaneous coronary intervention

BACKGROUND

In patients with poor left ventricular function and high-risk coronary lesions, prolonged ischemia during percutaneous coronary intervention (PCI) may have major hemodynamic consequences. The Tandemheart is a percutaneous left ventricular assist device intended for short-term circulatory support.

METHODS AND RESULTS

The Tandem-heart incorporates 9-17 F. arterial cannulae and a unique 21 F. transseptal cannula and centrifugal bloodpump. Operating at 7500 rpm, the pump withdraws oxygenated blood from the left atrium and delivers up to 4 liters/min to the arterial circulation. As of May 2001, the Tandem-heart was electively employed in three male patients (ages 52, 54 and 56) scheduled for high-risk PCI. The mean time to initial circulatory support was less than 30 minutes. Systemic hemodynamics significantly improved prior to PCI in two patients. Pump flow after one hour ranged from 2.43 to 3.8 liters/min (mean 3.17 liters/min) and duration of support from 23 to 49 hours (mean 33 hours). Procedural success was 100%, with no significant hemolysis or bleeding. Successful weaning was completed in all patients, who have remained free of major cardiac events up to seven months post-PCI.

CONCLUSIONS

In this first clinical experience of elective use of Tandem-heart for circulatory support during high-risk PCI, the device was easily inserted and preserved hemodynamic stability, regardless of the intrinsic cardiac function, creating optimism for more widespread use for this and other indications.