Simon Dushe

Safety and feasibility of a cardiac support device

The Cardiac Support Device (CSD), a preformed‐knitted polyester device surgically placed over the cardiac ventricles, prevents left ventricular (LV) remodeling and improves LV ejection fraction (EF) in dogs with heart failure (HF). This study was designed to examine the safety of the CSD in patients with advanced HF. As of December 31, 1999, the CSD was implanted into 22 patients with myocardial disease. Ten patients had concomitant mitral valve repair, two patients had valve replacement (one patient aortic and one patient mitral), one patient had LV assist device (LVAD) placement, and eight patients received only the CSD. The CSD was placed while on bypass with the heart beating, attached to the epicardium groove, and tailored anteriorly to snugly fit the ventricles. There were no intraoperative deaths or complications. Two patients died early from non‐CSD‐related causes 4 and 23 days postoperatively; one late death occurred. Of the remaining 19 patients, none had any CSD‐related adverse events during an average 3.5 ± 0.4 month follow‐up. All patients had completed 3‐month follow‐up. No patients had evidence of constrictive and/or restrictive physiology. Mitral valve regurgitation (MVR) improved in all patients.

Passive external cardiac constraint improves segmental left ventricular wall motion and reduces akinetic area in patients with non-ischemic dilated cardiomyopathy

OBJECTIVEnTo verify changes in left ventricular (LV) volumes and regional myocardial wall motion after implantation of a textile cardiac support device (CSD) for passive external constraint in non-ischemic dilated cardiomyopathy.nnnMETHODSnIn nine male patients participating in a non-randomized clinical trial LV volumes were determined and the segmental LV wall motion was studied by contrast-enhanced electron-beam CT in a sectionwise manner at three ventricular levels (base, middle and apex of ventricle) before and 32+/-6 months after CSD implantation. In 16 myocardial segments ejection fraction and wall thickening were measured semiautomatically after drawing the myocardial contours. The wall motion score index was calculated based on semiquantitative visual grading in each segment.nnnRESULTSnThe global LV volumes decreased significantly from 304.3 +/- 90.9 to 231.5 +/- 103.9 ml at end-diastole and from 239.7 +/- 83.7 to 164.0 +/- 97.7 at end-systole (P<0.05). Overall ejection fraction increased from 14.8 +/- 8.2 to 25.7 +/- 17.1% (P<0.05). A segment-by-segment analysis demonstrated a significant increase of regional ejection fraction in the basal myocardium as well as in the mid-inferior, mid-inferolateral, and mid-anterolateral myocardium. Overall wall thickening increased from 16.4 +/- 13.3 to 24.2 +/- 18.1% (P<0.05), but without significant differences in a segment-by-segment comparison. The mean wall motion score index improved from 2.70 +/- 0.26 to 2.20 +/- 0.71 (P<0.05), with an increased wall motion in eight (89%) patients. A section-by-section analysis demonstrated significantly improved wall motion in the inferior and lateral segments at each ventricular level. Postoperatively, the number of akinetic and markedly hypokinetic segments decreased significantly (P<0.05) from 56 (39%) to 26 (18%) and from 76 (53%) to 56 (37%), respectively.nnnCONCLUSIONnCSD implantation improves segmental wall motion, predominantly in the inferior and lateral myocardium, and reduces the number of akinetic and hypokinetic segments.

Effects of passive cardiac containment on left ventricular structure and function: verification by volume and flow measurements☆

BACKGROUNDnThe cardiac support device (CSD, Acorn) is a compliant, textile-mesh graft placed around the ventricles to prevent further dilatation and to improve function in congestive heart failure. The aim of this study was to verify post-operative changes in left ventricular volumes, ejection fraction, blood flow, and myocardial mass.nnnMETHODSnFourteen patients underwent contrast-enhanced, electrocardiography-triggered electron-beam computerized tomography before and 6 to 9 months after CSD implantation. We measured volume and flow using the slice-summation method and the indicator-dilution technique.nnnRESULTSnWe found significant changes for the following parameters: end-diastolic volume decreased from 382.9 +/- 140.2 ml to 311.3 +/- 138.7 ml, end-systolic volume from 310.4 +/- 132.4 ml to 237.4 +/- 133.8 ml, end-diastolic diameter from 75.3 +/- 7.8 mm to 70.7 +/- 11.6 mm, end-systolic diameter from 65.8 +/- 7.8 mm to 60.0 +/- 14.0 mm, and myocardial mass from 298.6 +/- 79.6 g to 263.1 +/- 76.8 g. Ejection fraction increased from 20.3% +/- 6.4% to 27.8% +/- 13.1%. We found no significant differences for stroke volume (from 72.5 +/- 24.6 ml to 73.8 +/- 23.6 ml), heart rate (from 80.5 +/- 11.0 beats per minute to 76.5 +/- 6.8 beats per minute), and total cardiac output (from 5.8 +/- 1.9 liter/min to 5.6 +/- 1.8 liter/min). Mitral regurgitation fraction decreased from 30.5% +/- 15.5% to 15.6% +/- 12.8%, increasing antegrade cardiac output from 3.8 +/- 0.9 liter/min to 4.7+/-1.5 liter/min. For most parameters, pre- and post-operative values in these patients differed significantly from those in an age- and gender-matched control group. In each patient, we observed a small hyperdense stripe along the pericardium after surgery, but we observed no local complications.nnnCONCLUSIONnThree-dimensional structural and functional data obtained by computerized tomography volume and flow measurements confirm the safety and efficacy of CSD implantation.

Quantification of mitral valve regurgitation by left ventricular volume and flow measurements using electron beam computed tomography: comparison with magnetic resonance imaging.

Purpose: This study was designed to evaluate electron beam computed tomography (CT) for quantifying mitral regurgitation in comparison with magnetic resonance (MR) imaging as a reference method. Method: Forty‐three patients, among them 33 with known mitral regurgitation, underwent electron beam CT and MR imaging. Total left ventricular stroke volume (TSV), antegrade stroke volume (ASV), and mitral regurgitation volume (MRV) and fraction (MRF) were determined and compared between the two modalities. Additionally electron beam CT measurements were compared with the corresponding echocardiographic findings. Results: Significant differences between electron beam CT and MR imaging were found for measurements of TSV and MSV but not for ASV and MRF. There was a close linear correlation between both modalities for all parameters. Furthermore, there was good agreement between electron beam CT and echocardiography, although electron beam CT shows a tendency to overestimate mitral regurgitation slightly. Conclusion: The results indicate that electron beam CT offers an additional procedure for quantifying mitral regurgitation and that it may be used as an alternative to MR imaging. Index Terms: computed tomography (CT), electron beam, echocardiography, heart valves, magnetic resonance (MR), mitral valve regurgitation.

Evaluation of left and right ventricular diastolic function by electron-beam computed tomography in patients with passive epicardial constraint.

Objective: Previous investigations have shown the usefulness of electron-beam computed tomography (EBCT) to describe ventricular diastolic function and to detect constrictive filling pattern. We used EBCT to analyze diastolic function in patients who underwent passive epicardial constraint because data describing ventricular filling in these patients are still incomplete. Methods: Ten patients with dilated cardiomyopathy (group 1) underwent EBCT examination before and again 6 months after surgery. Ten patients with normal diastolic function (group 2) and 5 male patients with constrictive pericarditis (group 3) served for comparison. Volume-time curves throughout the entire diastole were generated, and the rapidity of diastolic filling was assessed by calculating the percent filling fraction at consecutive EBCT frames throughout the diastole. Pericardial thickness was measured in a standardized fashion at different locations around both ventricles. Results: Early left ventricular filling pattern in group 1 did not change postoperatively (filling fraction at third diastolic frame was 50.0 ± 15.4% and 53.8 ± 14.4% before and after surgery, respectively) and was not significantly different from group 2 (48.7 ± 8.5%). In contrast, in group 3, early left ventricular filling was significantly accelerated (71.4 ± 9.3%) when compared with groups 1 and 2. A similar pattern was observed for the right ventricle. Pericardial thickness between groups 1 (1.22 ± 4.22 and 1.43 ± 0.39 mm before and after surgery, respectively) and 2 (1.38 ± 0.43 mm) did not differ significantly. In contrast, pericardium in group 3 was significantly thickened (4.93 ± 1.11 mm) when compared with both groups 1 and 2. Conclusions: The EBCT identified an abnormal accelerated diastolic filling and thickened pericardium in patients with constrictive pericarditis. Conversely, a normal diastolic filling pattern and pericardial thickness seem to be preserved in patients after passive epicardial constraint, when compared with baseline values and with normal subjects.

Results of Batista Procedure in Ischemic Dilated Cardiomyopathy

From March 1995 to April 1998, 24 men and 5 women (mean age, 62.2 ± 10 years) underwent the Batista procedure for end-stage cardiac dysfunction due to ischemic dilated cardiomyopathy. Preoperatively, mean cardiac index was 1.9 ± 0.3 L·min−1·m−2, stroke index was 25 ± 5 mL·beat−1·m−2, ejection fraction was 20% ± 6%, and 22 (79%) patients were in New York Heart Association functional class IV. Associated procedures were coronary bypass (25), mitral valvuloplasty (15), aortic or mitral valve replacement (5), dynamic cardiomyoplasty (2), and aneurysmectomy (1). One patient (3.4%) died early and 3 (10.3%) died later. The 1- and 2-year actuarial survival was 87%. A left ventricular assist device was required in 2 patients during the follow-up period. Postoperatively, cardiac index was 2.9 ± 0.3 L·min−1·m−2, stroke index was 36 ± 5 mL·beat−1·m−2, and ejection fraction was 38% ± 10%. Left ventricular end-diastolic diameter decreased from 71 ± 8 mm to 55 ± 8 mm. Currently, 88% of survivors are in functional class I or II. It was concluded that the Batista procedure significantly improved objective and subjective parameters of cardiac performance during early and intermediate follow-up.

Cardiac Support Device: Novel Surgical Option for Heart Failure

From April 1999 to July 2000, the Acorn cardiac support device was assessed in 22 patients with advanced heart failure, 10 of whom received mitral valve repair. There was 1 hospital death unrelated to the device, and 2 late deaths at 2 and 8 months postoperatively. The survivors had no device-related complications during a mean follow-up of 10.4 months. Mitral valve regurgitation improved in all patients and none had evidence of constrictive or restrictive physiology on repeat cardiac catheterization at 6 months. Preoperatively, 22% were in New York Heart Association functional class II, 71% in class III, and 7% in class IV. At 6 months postoperatively, 33% were in class I, 56% in class II, 11% in class III, and none in class IV. Ejection fraction increased from 19% ± 8% to 26% ± 10% at 3 months and 24% ± 11% at 6 months. Left ventricular end-diastolic diameter decreased from 74 ± 6.1 mm preoperatively to 68 ± 11 mm at 6 months. These findings indicate that the device is safe and effective in treating heart failure. Additional studies and longer follow-up are needed to confirm these results.