A simplified echocardiographic technique for detecting continuous-flow left ventricular assist device malfunction due to pump thrombosis

BACKGROUND

Malfunction of a continuous-flow left ventricular assist device (CF-LVAD) due to device thrombosis is a potentially life-threatening event that currently presents a diagnostic challenge. We aimed to propose a practical echocardiographic assessment to diagnose LVAD malfunction secondary to pump thrombosis.

METHODS

Among 52 patients implanted with a CF-LVAD from a single center who underwent echocardiographic pump speed-change testing, 12 had suspected pump thrombosis as determined by clinical, laboratory, and/or device parameters. Comprehensive echocardiographic evaluation was performed at baseline pump speed and at each 1,000-rpm interval from the low setting of 8,000 rpm to the high setting of 11,000 rpm in 11 of these patients.

RESULTS

Receiver operating characteristic curves and stepwise logistic regression analyses showed that the best diagnostic parameters included changes in the LV end-diastolic diameter (<0.6 cm), aortic valve opening time (<80 msec), and deceleration time of mitral inflow (<70 msec) from lowest to highest pump speed. One parameter was predictive of pump malfunction, with 100% sensitivity and 89% specificity, whereas 2 of 3 parameters increased the sensitivity to 100% and specificity to 95%.

CONCLUSIONS

The 3 echocardiographic variables of measured changes in LV end-diastolic diameter, aortic valve opening time, and deceleration time of mitral inflow between the lowest (8,000 rpm) and highest pump speed settings (11,000 rpm) during echo-guided pump speed-change testing appear highly accurate in diagnosing device malfunction in the setting of pump thrombosis among patients supported with CF-LVAD. Further investigation is warranted to create and validate a prediction score.

Transendocardial mesenchymal stem cells and mononuclear bone marrow cells for ischemic cardiomyopathy: the TAC-HFT randomized trial

IMPORTANCE

Whether culture-expanded mesenchymal stem cells or whole bone marrow mononuclear cells are safe and effective in chronic ischemic cardiomyopathy is controversial.

OBJECTIVE

To demonstrate the safety of transendocardial stem cell injection with autologous mesenchymal stem cells (MSCs) and bone marrow mononuclear cells (BMCs) in patients with ischemic cardiomyopathy.

DESIGN, SETTING, AND PATIENTS

A phase 1 and 2 randomized, blinded, placebo-controlled study involving 65 patients with ischemic cardiomyopathy and left ventricular (LV) ejection fraction less than 50% (September 1, 2009-July 12, 2013). The study compared injection of MSCs (n=19) with placebo (n = 11) and BMCs (n = 19) with placebo (n = 10), with 1 year of follow-up.

INTERVENTIONS

Injections in 10 LV sites with an infusion catheter.

MAIN OUTCOMES AND MEASURES

Treatment-emergent 30-day serious adverse event rate defined as a composite of death, myocardial infarction, stroke, hospitalization for worsening heart failure, perforation, tamponade, or sustained ventricular arrhythmias.

RESULTS

No patient had a treatment-emergent serious adverse events at day 30. The 1-year incidence of serious adverse events was 31.6% (95% CI, 12.6% to 56.6%) for MSCs, 31.6% (95% CI, 12.6%-56.6%) for BMCs, and 38.1% (95% CI, 18.1%-61.6%) for placebo. Over 1 year, the Minnesota Living With Heart Failure score improved with MSCs (-6.3; 95% CI, -15.0 to 2.4; repeated measures of variance, P=.02) and with BMCs (-8.2; 95% CI, -17.4 to 0.97; P=.005) but not with placebo (0.4; 95% CI, -9.45 to 10.25; P=.38). The 6-minute walk distance increased with MSCs only (repeated measures model, P = .03). Infarct size as a percentage of LV mass was reduced by MSCs (-18.9%; 95% CI, -30.4 to -7.4; within-group, P = .004) but not by BMCs (-7.0%; 95% CI, -15.7% to 1.7%; within-group, P = .11) or placebo (-5.2%; 95% CI, -16.8% to 6.5%; within-group, P = .36). Regional myocardial function as peak Eulerian circumferential strain at the site of injection improved with MSCs (-4.9; 95% CI, -13.3 to 3.5; within-group repeated measures, P = .03) but not BMCs (-2.1; 95% CI, -5.5 to 1.3; P = .21) or placebo (-0.03; 95% CI, -1.9 to 1.9; P = .14). Left ventricular chamber volume and ejection fraction did not change.

CONCLUSIONS AND RELEVANCE

Transendocardial stem cell injection with MSCs or BMCs appeared to be safe for patients with chronic ischemic cardiomyopathy and LV dysfunction. Although the sample size and multiple comparisons preclude a definitive statement about safety and clinical effect, these results provide the basis for larger studies to provide definitive evidence about safety and to assess efficacy of this new therapeutic approach.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00768066.

Safety of serial MRI in patients with implantable cardioverter defibrillators

OBJECTIVE

While patients with cardiac implantable electronic devices could benefit from magnetic resonance (MR) imaging, the presence of such devices has been designated as an absolute contraindication to MR. Although scanning algorithms are proposed for cardiac implantable electronic devices, their safety remains uncertain. To address this issue, the safety of serial cardiac MR scans was evaluated in patients with implantable cardioverter defibrillators (ICDs).

METHODS

Three serial cardiac MR scans were prospectively performed at 1.5 T on 10 patients (9 men) of median age 56 years (range 51-68) with ICDs. ICD interrogation was performed before and after the MR scan and at a follow-up of median 370 days (range 274-723). Image quality was also assessed.

RESULTS

In all patients MR scanning occurred without complications. There were no differences between pre- and post-MR pacing capture threshold, pacing lead or high voltage lead impedance, or battery voltage values. During follow-up there were no occurrences of ICD dysfunction. Although most patients had image artifacts, the studies were generally diagnostic regarding left ventricular function and wall motion. Delayed enhancement imaging was of good quality for inferior wall and inferolateral infarcts, but ICD artifacts often affected the imaging of anterior wall infarcts.

CONCLUSION

Serial MR scans at 1.5 T in patients with ICDs, when carefully performed in a monitored setting, have no adverse effects on either patient or device. When required, single or multiple MR scans at 1.5 T may therefore be considered for clinical diagnostic purposes in these patients.

Biomarkers of oxidative stress in heart failure

Oxidative stress is the relative excess of reactive oxygen species (ROS) versus endogenous defense mechanisms. Abundant evidence has demonstrated the role of ROS, along with reactive nitrogen species (RNS), in the pathophysiology of cardiovascular disease, including heart failure. Many biomarkers of oxidative stress have been studied as surrogates of oxidative damage. Recently, markers of impaired nitric oxide signaling have also been identified. Many biomarkers have been associated with prognosis and mortality, and some may even be modified by therapy. However, the clinical utility is limited by less than optimal standardization techniques and the lack of sufficient large-sized, multimarker prospective trials.