Donald J. Magilligan

Implantable electrical left ventricular assist systems: Bridge to transplantation and future

An implantable left ventricular assist system (LVAS) utilizing an electromechanically driven dual pusher-plate blood pump has been employed in a multiinstitutional trial as a bridge to cardiac transplantation. Under development for permanent circulatory support in patients with end-stage heart disease, the LVAS, in this application, derives power and control from an external console via a percutaneous lead. The LVAS was implanted in 20 patients (16 men, 4 women) who were hemodynamically unstable or in refractory cardiogenic shock. The mean age was 44.9 years (range, 25 to 63 years). Preoperative diagnosis was evenly divided between end-stage ischemic disease, cardiomyopathy, and acute myocardial infarction. Implanted in the left upper quadrant within the anterior abdominal wall, the blood pump was connected between the left ventricular apex and ascending aorta. Total support of the systemic circulation and substantial left ventricular unloading were achieved with synchronous counterpulsation for periods up to 90 days (mean, 22.7 days). All patients were stabilized hemodynamically. The mean preoperative cardiac index of 1.5 L/min/m2 increased by a factor of 2. Pulmonary arterial pressures decreased substantially. Serious complications occurred in 16 patients, precluding cardiac transplantation in 10. Most complications (greater than 70%) were in patients who did not receive transplants; the most common complication was bleeding. Twelve of 13 patients with LVAS implants for more than seven days were mobilized, and 4 were fully ambulatory and completely rehabilitated. Orthotopic cardiac transplantation was performed in 10 patients after implants ranging from two to 90 days (mean, 30.3 days).(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous Degeneration of Porcine Bioprosthetic Valves

From October, 1971, to October, 1979, 490 patients with 560 porcine bioprosthetic valves were discharged from the hospital. During these 8 years, 23 valves were removed because of failure due to spontaneous degeneration. Bioprosthetic valve survival without degeneration was at 4 years, 98.9% +/- 86 (standard error); at 5 years, 96.4% +/- 1.3; at 6 years, 90.8% +/- 2.4; and at 7 years, 84.2% +/- 3.7. There was no difference in degeneration observed with regard to sex, valve position, or whether the valves were rinsed with antibiotics prior to implantation. There was an increase in degeneration in patients 35 years old and younger compared with those more than 35 years old (p = 0.0001). Valve failure was gradual, and valve changes were noted by echocardiogram and phonocardiogram prior to actual failure. Specific factors leading to degeneration require further investigation.

Can computed tomography of the chest stage lung cancer?—Yes and no

To determine the accuracy of computed tomography (CT) of the chest in the staging of lung cancer, we studied 418 patients with primary pulmonary carcinoma between 1979 and 1986. Each had a preoperative scan performed before detailed operative staging. Each CT scan was analyzed for components of the current TNM staging system. Computed tomography sensitivity and specificity for mediastinal lymph node metastasis were 84.4% and 84.1%, with corresponding positive and negative predictive accuracies of 68.7% and 92.9%, respectively. When TNM stages were derived from CT scans, only 190 of 418 (45.4%) completely agreed with operative staging. An additional 53 of 418 (12.7%) predicted the correct stage, although components of the TNM system were incorrect. In 94 of 418 scans (22.5%) CT overestimated the stage, whereas in 81 (19.4%) CT downgraded the stage. Computed tomography suggested metastatic lesions in liver, lung, adrenal gland, bone, or abdominal lymph nodes in 40 of 373 scans (10.7%); only five of 40 (12.5%) had documented metastasis. In summary, CT of the chest cannot accurately stage primary lung carcinoma according to the TNM classification. Because the negative predictive accuracy for mediastinal lymph node metastasis remains high (92.9%), invasive staging can be deferred for definitive thoracotomy when no lymphadenopathy is evident on CT. The high negative predictive accuracy for scans of the chest and upper abdomen makes CT a useful tool for exclusion of metastatic disease.

The Porcine Bioprosthetic Heart Valve: Experience at 15 Years

The porcine bioprosthetic valve has been in use at Henry Ford Hospital since 1971. In this review, 980 patients with 1,081 porcine bioprosthetic valves were examined from 1 month to 16.4 years after implantation with a 99% complete follow-up. Patient survival was 59% +/- 2.2% (+/- standard error of the mean) at 10 years and 38% +/- 4.0% at 15 years. Factors associated with decreased survival after hospital discharge were age greater than 35 years and New York Heart Association functional class IV. Freedom from thromboembolism was 92% +/- 1.2% at 10 years and 89% +/- 3.2% at 15 years. Freedom from endocarditis was 93% +/- 1.2% at 10 years and 92% +/- 1.3% at 15 years. Freedom from structural valve degeneration for all valves was 71% +/- 2.6% at 10 years and 31% +/- 5.6% at 15 years. Factors associated with increased risk of structural valve degeneration were age younger than 35 years, female sex, and preoperative cardiac index greater than 2 L/min/m2. Among a total of 172 patients undergoing removal of a degenerated valve, mortality was 12.5%, and significant risk factors for death at reoperation were emergency operation and functional class IV. Experience with the porcine bioprosthetic valve after 15 years suggests that its use be confined to older patients or patients with a contraindication of anticoagulation.

Doppler and echocardiographic features of normal and dysfunctioning bioprosthetic valves

Echocardiographic and Doppler studies were performed on 183 clinically normal and 58 severely dysfunctioning bioprosthetic mitral, aortic and tricuspid valves. The valve dysfunction resulted from spontaneous cusp degeneration in 49 instances and from paravalvular regurgitation in 9. The pulsed Doppler study demonstrated regurgitant flow in 36 (92%) of 39 regurgitant valves and 8 (90%) of 9 paravalvular regurgitant valves. Diagnostic echocardiographic features were present in only 51 and 10% of the patients, respectively. Although the Doppler regurgitant jet was peripheral in seven of the nine patients with paravalvular regurgitation, it was not possible to differentiate these patients from those who had valve degeneration and cusp tear at the periphery of the valve ring. Eight patients presented with a musical holosystolic murmur of mitral insufficiency. In all eight there was a characteristic honking intonation on the audio signal and a striated shuddering appearance on the video Doppler signal. Ten stenotic mitral bioprosthetic valves (less than or equal to 1.1 cm2 valve orifice) were identified by Doppler study. Diagnostic echocardiographic features were present in only two of these patients. The Doppler-derived valve orifice dimension correlated well (r = 0.83) with cardiac catheterization values. Fourteen asymptomatic or minimally symptomatic patients had echocardiographically thickened mitral cusps (greater than or equal to 3 mm). These patients had a significantly (p less than 0.0001) smaller valve area as compared with normal control valves, and during 4 to 24 months of follow-up, five of these patients developed severe valve regurgitation or stenosis. Doppler ultrasound is more sensitive than echocardiography in diagnosing bioprosthetic valve stenosis and regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Early extubation after coronary artery bypass: brief report.

We performed a prospective study of early postcoronary artery bypass graft (CABG) ventilator management and weaning. Sixty-three patients were studied consecutively; 27 were managed by the standard post-CABG weaning practice at this institution, and 36 were managed by respiratory therapists using a protocol with specific ventilation and weaning guidelines. The mean time to extubation was decreased by 41% using the protocol. Arterial blood gas sampling was reduced 42%. There were no deaths in either group. Physicians were alerted to problems necessitating interruption of the protocol in six of 36 patients studied. This protocol proved easy to follow and safe in the hands of respiratory therapists. It lowered costs and improved patient comfort.

M mode and two dimensional echocardiographic features of porcine valve dysfunction

The echocardiographic features are presented of degeneration of nine glutaraldehyde-fixed porcine xenograft valves implanted in eight patients. These features occurred 11 to 68 months after implantation and were correlated with surgical and necropsy findings. Acute bacterial endocarditis was present in two patients, and had been successfully treated medically in three other patients 47 to 52 months before valve degeneration was recognized. The valve was severely thickened in four patients and in two of the four the thickening was associated with a significant hemodynamic transvalve gradient. M mode echocardiography demonstrated increased thickness and loss of the cusp detail. In five patients severe regurgitation due to a tear in one or more cusps developed in the the valve in the mitral position. M mode echocardiography in all five patients revealed on the valve systolic or diastolic fluttering echoes, or both. The two dimensional echocardiogram demonstrated thickened cusps with systolic protrusion of the leaflets into the left atrium. Both modes of echocardiography were of valve in identifying degeneration of the porcine xenograft valve.

Is the Hancock Porcine Valve the Best Cardiac Valve Substitute Today

Valve replacement with the Hancock stabilized glutaraldehyde porcine aortic valve has been accomplished in 454 patients. Hospital mortality (influenced by a high proportion of patients in New York Heart Association Functional Class IV) was 17.6% (80/454). The first 221 patients discharged from hospital were followed for 36 to 75 months after valve replacement. There have been 26 late deaths among these patients; 88% (195/221) are alive. Of these 221 patients, 185 had single-valve replacement, (125 mitral and 60 aortic), and 36 underwent multiple-valve replacement. There have been 260 valves at risk up to 6 1/4 years, which is equivalent to 12,984.5 valve-months or 1,082 valve-years. Average follow-up is 4.16 years. There have been 13 valve failures in 10 patients. In 4 patients endocarditis was proved to be the cause of failure, and in 5 it was suspected; in 1 patient the failure the failure is unexplained. The pathological similarity between those in whom infection was documented and the other 5 is remarkable and raises the question of whether low-grade infections may be the cause of certain types of valve failure.

Frequency spectra of the first heart sound and of the aortic component of the second heart sound in patients with degenerated porcine bioprosthetic valves

To determine the usefulness of the frequency of heart sounds in the assessment of porcine bioprosthetic valve degeneration, frequency spectra of phonocardiograms of the first heart sound and the aortic component of the second sound were analyzed in 31 patients with degenerated porcine bioprosthetic valves. Comparisons were made with 35 control patients whose valves were inserted 1 month or less. Among 23 patients with degenerated porcine bioprosthetic valves in the mitral position, the dominant frequency of the first heart sound was 95 +/- 11 Hz, which exceeded the first sound in 18 controls (51 +/- 3 Hz) (p less than 0.01). The degenerated mitral porcine bioprosthetic valves of 14 patients showed calcification or fibrosis and the first heart sound in these patients was 115 +/- 16 Hz, which exceeded that of control subjects (p less than 0.001). The degenerated mitral porcine bioprosthetic valves of 9 patients showed torn leaflets only, and the first heart sound in these patients was 64 +/- 9 Hz, which did not differ from that of control subjects. In the aortic position, 8 valves were degenerated and the aortic component of the second sound was 109 +/- 12 Hz, which was higher than that in 17 control subjects (63 +/- 4 Hz) (p less than 0.001). Only 2 of these degenerated valves showed tears unaccompanied by calcific deposits or fibrosis, and the frequencies were comparable to that of control subjects. These observations indicate that the frequency of heart sounds in patients with degenerated porcine bioprosthetic valves becomes abnormally elevated when degeneration is accompanied by calcification or fibrosis, which causes the cusps to stiffen.

Bacteremia, endocarditis, and the Hancock valve.

Among 373 patients with porcine xenografts, there were 27 instances of exposure of the xenograft to bloodstream or endocardial infection in 22 patients. Nine patients underwent 10 separate insertions of xenografts for active infective endocarditis. There were no early infections or valve failures. Three patients returned with a late prosthetic valve endocarditis (PVE) due to a new infection. There were 6 instances of bacteremia early after xenograft valve insertion with no early infection, no valve dysfunction, and 1 instance of late PVE. Eleven patients had PVE on a porcine xenograft. Blood cultures in the 10 patients treated with antibiotics promptly became negative. There were 3 valve-related deaths: 2 from valve incompetence and 1 from mitral and aortic xenograft stenosis. Our experience suggests that the Hancock porcine xenograft is: (1) as resistant to infection as are rigid prostheses in active infective endocarditis; (2) resistant to early postoperative bacteremias; and (3) easier to sterilize than rigid prostheses and more durable than other tissue valves in the face of PVE.