Graftmaster savior: Injury to a patent LIMA during pericardiectomy, when a covered stent came to the rescue

A 71-year-old male with multivessel coronary artery disease who underwent bypass with saphenous vein grafts to a Marginal branch and distal RCA and LIMA to LAD in 1988, DM II, atrial fibrillation on Coumadin, TIA, obstructive sleep apnea and pulmonary hypertension was referred to our institution after extensive dyspnea evaluation with a diagnosis of constrictive pericarditis for pericardiectomy. He had normal left ventricular function, moderate mitral and tricuspid regurgitation. Coronary angiography revealed ostial LAD CTO, patent LIMA to mid LAD, second Marginal branch CTO with left-to-left collaterals and mid RCA CTO with left-to-right collaterals. Vein grafts to the Marginal branch and distal RCA were occluded. The pericardium was heavily calcified on CT of the chest. The LIMA was inadvertently injured leading to acute STEMI and ventricular fibrillation arrest treated with defibrillation once. Surgical repair was unsuccessful. A Graftmaster covered stent was successful deployed with restoration of TIMI III flow to the LAD territory. Pericardiectomy was completed via both the median resternotomy and left thoracotomy. Triple therapy with Aspirin, Clopidogrel, and Coumadin was initiated and maintained for 3 months without hemorrhagic or thrombotic complications. He has continued to do well in follow-up on Clopidogrel and Coumadin.

Platelet and Fibrinogen Survival in Calves Implanted with Artificial Heart and Ventricular Assist Device -Correlation with Autopsy Findings

The two main ingredients of blood clots formed on artificial surface are platelets and fibrinogen. In this study, we measured platelet and fibrinogen survival in calves implanted with total artificial heart (TAH) and left ventricular assist device (LVAD), and correlate these data with autopsy findings. Platelet survival with autologous 111In-labeled platelets was performed on nine calves implanted with TAH and five with LVAD. Fibrinogen survival with 131I-labeled homologous fibrinogen was performed on six calves with TAH and three with LVAD. Platelet survival was significantly shortened in both groups of animals: 5.89 ± 0.52 days, control 6.46 ± 0.31 days, p = 0.0013; fibrinogen survival was normal: 8.79 ± 1.20 days, control 8.64 ± 1.16 days. At autopsy two calves with TAH had multiorgan thromboembolism. Two other animals with TAH and four with LVAD had focal renal infarcts. Most animals had minor clot formation within the prosthetic device. Major septic complications occurred in four calves with TAH and one with LVAD. Continuous platelet activation by artificial surface probably explains the shortened platelet survival and thromboembolic complications.

Ambulatory extra-aortic counterpulsation in patients with moderate to severe chronic heart failure

OBJECTIVES

The study sought to assess feasibility, safety, and potential efficacy of a novel implantable extra-aortic counterpulsation system (C-Pulse) in functional class III and ambulatory functional class IV heart failure (HF) patients.

BACKGROUND

30% to 40% of HF patients suffer from poor functional status and quality of life (QoL) but are not in need of end-stage treatments. We undertook a multicenter single-arm study to assess the C-Pulse System in such patients.

METHODS

New York Heart Association (NYHA) functional class III or ambulatory functional class IV HF patients were eligible. Safety was assessed continuously through 12 months. Efficacy measurements included changes from baseline to 6 and 12 months in NYHA functional class, Minnesota Living with Heart Failure (MLWHF) and Kansas City Cardiomyopathy Questionnaire (KCCQ) scores, 6-min walk distance (6MWD), and exercise peak oxygen consumption (pVO2; 6 months only).

RESULTS

Twelve men and 8 women (56.7 ± 7 years, 34 to 71 years of age) with ischemic (n = 7) or nonischemic (n = 13) cardiomyopathy were implanted. There was no 30-day mortality and no neurological events or myocardial infarctions through 12 months. At 6 months, there were 3 deaths (1 device-related). One-year survival was 85%. At 6 months, C-Pulse produced improvements in NYHA functional class (3.1 ± 0.3 to 1.9 ± 0.7, p = 0.0005), MLWHF (63.6 ± 19.9 to 40.2 ± 23.2, p = 0.0005), and KCCQ scores (43.6 ± 21.1 to 65.6 ± 21.5, p = 0.0002), but not 6MWD (275.5 ± 64.0 to 296.4 ± 104.9, p = NS) or pVO2 (14.5 ± 3.6 to 13.1 ± 4.4, p = NS). Improvements continued at 12 months, with 6MWD change becoming statistically significant (336.5 ± 91.8, p = 0.0425).

CONCLUSIONS

Use of C-Pulse in this population is feasible, appears safe, and improves functional status and QoL. A prospective, multicenter, randomized controlled trial is underway. (C-Pulse IDE Feasability Study-A Heart Assist System; NCT00815880).

Clinical Experience With Sternotomy Versus Subcostal Approach for Exchange of HeartMate II Left Ventricular Assist Device

BACKGROUND

The safety and efficacy of exchanging the HeartMate II (Thoratec Corp, Pleasanton, CA) left ventricular assist device (LVAD) through a less invasive subcostal approach remains unclear.

METHODS

We reviewed the records of 17 patients who underwent exchange of their HeartMate II device at our institution since 2007. We divided the cohort into devices exchanged through a subcostal (SC) approach versus a median sternotomy (MS) approach and obtained data pertaining to the short- and long-term outcomes.

RESULTS

Nine patients had pump exchange through an MS approach versus 8 patients who underwent an SC approach. The mean duration of support with the first pump was 540 ± 450 days. The reason for exchange was electromechanical failure (7 patients), thrombosis (8 patients), and infection (2 patients). There were no 30-day perioperative deaths with either approach. Compared with sternotomy, patients who underwent an SC approach had significantly shorter operative times (131 vs 222 minutes; p = 0.001) and lower reoperation rates for bleeding (0 vs 44.4%; P = 0.05) and required fewer transfused blood products (packed red cells, 3.5 units vs 7.1 units; p < 0.05; cryoprecipitate, 50.7 mL vs 209.3 mL; p = 0.01; and platelets, 292 mL versus 762 mL; p < 0.05). Additionally, patients who underwent an SC approach had shorter postoperative stays in the intensive care unit (ICU) (5 days vs 13.8 days; p < 0.05) and shorter total hospital stays (16.4 days vs 27.2 days; p < 0.05). Long-term survival after mean follow-up of 260 days for the SC group and 232 days for the sternotomy group was 75% and 33%, respectively.

CONCLUSIONS

Exchange of the HeartMate II pump can be accomplished with low morbidity and mortality and good long-term outcomes through a less invasive SC approach.

Comparison of hemolysis between CentriMag and RotaFlow rotary blood pumps during extracorporeal membrane oxygenation

The purpose of this investigation was to compare the hemolysis levels for patients on extracorporeal membrane oxygenation (ECMO) incorporating two different rotary blood pumps (CentriMag [CMAG] and RotaFlow [RF]) in identical circuits otherwise. The difference between the two pumps is the cost. One is 20-30 times less expensive than the other. A retrospective analysis of all patients placed on ECMO from June 2008 through May 2012 was done to evaluate hemolysis. Daily plasma hemoglobin (pHb), lactate dehydrogenase (LDH), and lactate levels were collected on all patients. Values were compared between those patients who received a CMAG and those who received an RF. Patients had to be on ECMO for more than 2 days to be included in the study. Linear mixed effects models were fit to the data to assess differences over time for each continuous outcome. Forty patients were placed on ECMO incorporating CMAG, whereas 40 patients received an RF. There were no significant statistical differences between CMAG and RF groups when comparing days on support (8.7 ± 5.0; 8.4 ± 5.7), age (44.8 ± 18.3; 46.1 ± 16.0), body surface area (2.03 ± 0.36; 1.96 ± 0.31), gender (male: 58%, female: 42%; male: 55%, female: 45%), etiology, type of support (veno-arterial [VA)]: 78%, veno-venous [VV)]: 22%; VA: 82%, VV: 18%) and pre-ECMO LDH levels (4004.0 ± 3583.2; 3603.7 ± 3354.1). There were also no significant differences between the CMAG and RF groups when comparing the mean values for daily pHb levels (5.7 ± 3.6; 5.7 ± 4.2), lactate levels (2.8 ± 1.9; 3.0 ± 2.1), and LDH levels (2656.3 ± 1606.8; 2688.6 ± 1726.1) or daily lactate, LDH, and pHb levels for the first 10 days of support. From our investigation, there is no difference between the CMAG and the RF blood pumps in regard to the creation of hemolysis during ECMO. The difference in cost of the devices does not correlate with the performance and outcomes.

Management of left ventricular distension during peripheral extracorporeal membrane oxygenation for cardiogenic shock

The application of peripheral veno-arterial extracorporeal membrane oxygenation in the management of inotrope-refractory cardiogenic shock has proven controversial because of concerns about sub-optimal drainage of the left heart, resulting in left ventricular distension and pulmonary oedema. In this article, we will discuss the pathophysiological basis and clinical implications of left ventricular distension following institution of peripheral extracorporeal life support. We will also review the clinical strategies used to circumvent left ventricular distension and pulmonary oedema in these patients.

The new role of the perfusionist in adult extracorporeal life support

Adult and pediatric extracorporeal life support (ECLS) has been transformed by the European(1) and Australian( 2) experiences with a reduction of the circuit to its most basic form (Figure 1). Many factors have converged at this point in time to allow us to offer this support. The availability in the U.S.A. of an advanced oxygenator (Quadrox(D)) (Maquet Inc., Bridgewater, NJ), long-term centrifugal pumps and circuit coatings offers us the means to provide ECLS. The other equally important factor is the intensivist trained in extracorporeal therapies. Once the intensive care unit registered nurse (ICU RN) is trained to safely and effectively manage both the patient and ECLS circuit, this support may be offered. The perfusionist is in an unique position to educate and mentor the ICU RN in ECLS. There is, perhaps, no one in a better position to explain this equipment and its uses in an interdisciplinary-oriented pediatric and adult ECLS program than a perfusionist.

A passively suspended Tesla pump left ventricular assist device

The design and initial test results of a new passively suspended Tesla type left ventricular assist device blood pump are described. Computational fluid dynamics (CFD) analysis was used in the design of the pump. Overall size of the prototype device is 50 mm in diameter and 75 mm in length. The pump rotor has a density lower than that of blood and when spinning inside the stator in blood it creates a buoyant centering force that suspends the rotor in the radial direction. The axial magnetic force between the rotor and stator restrain the rotor in the axial direction. The pump is capable of pumping up to 10 L/min at a 70 mm Hg head rise at 8,000 revolutions per minute (RPM). The pump has demonstrated a normalized index of hemolysis level below 0.02 mg/dL for flows between 2 and 9.7 L/min. An inlet pressure sensor has also been incorporated into the inlet cannula wall and will be used for control purposes. One initial in vivo study showed an encouraging result. Further CFD modeling refinements are planned and endurance testing of the device.

Successful treatment of peripartum cardiomyopathy with extracorporeal membrane oxygenation

A 24-year-old female developed heart failure within four months of delivering her first child. Echocardiogram revealed a moderately dilated left ventricle with severely reduced systolic function. She continued to decompensate, requiring intubation and inotropic support. When the use of an intra-aortic balloon pump failed to stabilize the patient, the decision was made to place her on ECMO. The circuit consisted of a Quadrox D membrane oxygenator and a CentriMag® centrifugal pump. After 11 days of support, the patient met the weaning criteria and was successfully removed from ECMO. She was discharged one month after her admission. The new technology available allows for ECMO to be considered as an earlier option for the treatment and management of these patients as a bridge to recovery.

INTERMACS: interval analysis of registry data

BACKGROUND

The Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) is an NIH-sponsored registry of US FDA-approved mechanical circulatory support devices (MCSDs) used for destination therapy, bridge to transplantation (BTT), or recovery of the heart. INTERMACS data were analyzed through the most recent quarter ending March 31, 2008.

STUDY DESIGN

INTERMACS variables include demographics, patient outcomes (survival and adverse events), hemodynamic data, and laboratory values. Data were analyzed with competing outcomes methods. Risk factors were identified for death and transplantation.

RESULTS

Ninety-four sites have prospectively enrolled 483 patients in INTERMACS (BTT, 80%; destination therapy, 15%; bridge to recovery, 5%). Forty-two percent of patients had critical cardiogenic shock before implantation, 38% had progressive circulatory decline despite inotropic agents, and 8% were stable but inotropic agent-dependent. The remaining 12% had recurrent advanced heart failure, severe exercise intolerance, or advanced class III heart failure. At 6 months postimplantation, the competing outcomes for the 483 patients included ongoing support (42%), cardiac transplantation (33%), cardiac recovery with pump removal (3%), or death (22%). The most common causes of death were central nervous system events (11%), cardiovascular failure (8%), or respiratory failure (8%). Less common causes were infection (4%), device malfunction (4%), and liver failure (3%). Survival for BTT and destination therapy were similar (p = 0.53). Patient profile at the time of implantation (critical cardiogenic shock versus others) influenced survival (p = 0.007), as did device configuration (left ventricular assist device versus biventricular ventricular assist device; p < 0.0001).

CONCLUSIONS

INTERMACS has increasing participation among domestic MCSD centers. The influence of preimplantation patient condition on survival underscores the importance of timely referral before critical cardiogenic shock occurs. As more devices achieve US FDA approval, INTERMACS will become useful for comparing MCSDs.

The Effect of Left Ventricular Function and Drive Pressures on the Filling and Ejection of a Pulsatile Pediatric Ventricular Assist Device in an Acute Animal Model

Penn State is currently developing a 12-mL, pulsatile, pneumatically driven pediatric ventricular assist device intended to be used in infants. After extensive in vitro testing of the pump in a passive-filling, mock circulatory loop, an acute animal study was performed to obtain data with a contracting ventricle. The objectives were to determine the range of pneumatic pressures and time required to completely fill and empty the pediatric ventricular assist device under various physiologic conditions, simulate reductions in ventricular contractility and blood volume, and provide data for validation of the mock circulatory loop. A 15-kg goat was used. The cannulation was achieved via left thoracotomy from the left ventricle to the descending aorta. The pump rate and systolic duration were controlled manually to maintain complete filling and ejection. The mean ejection time ranged from 280 ms to 382 ms when the systolic pressure ranged from 350 mm Hg to 200 mm Hg. The mean filling time ranged from 352 ms to 490 ms, for the diastolic pressure range of -60 mm Hg to 0 mm Hg. Esmolol produced a decrease in left ventricular pressure, required longer pump filling time, and reduced LVAD flow.

Comparison of LionHeart LVAD-implanted calves based on renal infarctions

Calves implanted with the LionHeart left ventricular assist device during the Food and Drug Administration Investigational Device Exemption (IDE) trial had fewer renal infarctions than calves implanted after this trial (post-IDE). Since a decrease in renal infarctions indicates a favorable outcome, we compared nine IDE with 16 post-IDE implantations. Renal infarct severity was graded (0 to 4) on the basis of necropsy reports, histopathology reports, and photographs. Implants were compared for duration of support, anticoagulation, device flow, percent fill, device rate, free plasma hemoglobin, fibrinogen, platelet count, nonsteroidal anti-inflammatory drug use, inlet cannula shape, and outlet graft-to-graft anastomosis technique. IDE calves had lower renal pathology scores (1.8 vs. 2.8, p = 0.03), mean device percent fill (88.5% vs. 94.0%, p = 1 x 10), and median free plasma hemoglobin (2.6 vs. 4.4 mg/dL, p = 0.01). IDE animals also had a higher mean device rate (108 vs. 98 bpm, p = 0.04), received low-molecular-weight dextran in the early postoperative period, began oral warfarin earlier, had straighter inlet cannulae, and had factory-sewn outlet graft-to-graft anastomoses. Duration of support did not predict severity of renal infarction, and there were no differences in device flow, international normalized ratio, platelet count, or nonsteroidal anti-inflammatory drug use. These results could assist future implantations.

Does total implantability reduce infection with the use of a left ventricular assist device? The LionHeart experience in Europe

BACKGROUND

Infection is the leading cause of death for left ventricular assist device (LVAD) patients with end-stage heart failure. Decreased infection may be possible with fully implantable LVADs such as the LionHeart, which lacks percutaneous conduits (PCs), a common source of device-related infection (DRI). This sub-study reports infections with the LionHeart and compares these results with historic data from the REMATCH trial, bridge to recovery (BTR) and bridge-to-transplantation (BTT) studies.

METHODS

Twenty-three patients were implanted with the LionHeart LVAD and followed until death or heart transplant during a non-randomized, multicenter, European trial from October 1999 to April 2004. The nature and incidence of infection were analyzed and adjudicated to definitions similar to, or the same as, the REMATCH definitions.

RESULTS

The combined number of implant days was 7,980, with a mean of 347 days (median 112, range 17 to 1,259 days). Survival at 1 year was 39%, with 2-year survival at 22%. Seventy-four percent of patients developed one or more infections, with 30% developing sepsis, and 35% developing pump-pocket infections (PSIs). No patients developed pump-housing or inflow- or outflow-tract infections (PI). For comparison, the prevalence rates of sepsis, PSI and PI in REMATCH were 51%, 35% and 19%, respectively.

CONCLUSIONS

The patients in the European LionHeart Clinical Utility Baseline Study (CUBS) trial had less sepsis and less overall DRI compared with the REMATCH LVAD group. Therefore, the fully implanted device may cause less infection than PC devices during destination therapy (DT). Although lower for DT, these rates are still higher than for some BTT experiences. Areas for future improvement include miniaturization of controller/battery components to reduce wound complications related to pocket size, and installation of more modern lithium-ion batteries to decrease the need for re-operations due to battery end-of-life.

Initial United States experience with the Paracor HeartNet⁎⁎Paracor Medical, Inc, Sunnyvale, Calif. myocardial constraint device for heart failure

OBJECTIVE

This study was undertaken to review the initial results and surgical safety data for the US Food and Drug Administration safety and feasibility trial of the Paracor HeartNet (Paracor Medical, Inc, Sunnyvale, Calif.) myocardial constraint device.

METHODS

Patients with New York Heart Association functional class II or III heart failure underwent device implantation (n = 21) through a left minithoracotomy.

RESULTS

The average age was 53 years (31-72 years). There were 18 men and 3 women, and 17 patients had nonischemic etiology of heart failure. Mean heart failure duration was 8.3 years (1.4-18.8 years). Average ejection fraction was 22% (11%-33%), with an average left ventricular end-diastolic dimension of 74 mm (55-94 mm). Previous medical therapy included angiotensin-converting enzyme inhibitors, beta-blockers, diuretics, digoxin, and aldosterone receptor blockers. At implantation, 17 patients had implantable electronic devices: 1 biventricular pacemaker, 11 biventricular pacemakers with cardioverter-defibrillators, and 5 implantable cardioverter-defibrillators. Patient comorbidities included hypertension in 10 cases, diabetes mellitus in 8, myocardial infarction in 1, and ventricular tachycardia in 8. Mean operative time was 68 minutes (42-102 minutes), and implantation time averaged 15 minutes (5-51 minutes). The average time to ambulation was 1.6 days (1-4 days). The intensive care unit stay averaged 3.3 days (1-16 days), and hospital stay averaged 6.3 days (4-16 days). Atrial fibrillation occurred in 2 patients, and there were 2 in-hospital deaths.

CONCLUSIONS

The Paracor device can be implanted in patients with heart failure and reduced left ventricular function with a high degree of success. Significant surgical complications were infrequent. The initial US experience supports the conduct of a randomized, controlled, pivotal trial.

Neurologic Events With a Totally Implantable Left Ventricular Assist Device: European LionHeart Clinical Utility Baseline Study (CUBS)

BACKGROUND

Neurologic events such as thromboembolic and hemorrhagic strokes are common complications of mechanical circulatory support. We report the neurologic events observed in patients treated for end-stage heart failure with the implantable, pulsatile LionHeart left ventricular assist device (LVAD). This sub-study was part of the LionHeart European Clinical Utility Baseline Study (CUBS).

METHODS

Twenty-three male patients were implanted with the LionHeart LVAD in a non-randomized, observational study. Neurologic events were classified into three categories: (1) transient ischemic attacks (TIAs); (2) strokes, including cerebrovascular accidents (CVAs) and intracranial bleeding (ICB); and (3) "other," including hypoperfusion, coma and brain death. Neurologic injuries were also categorized as transient/reversible or permanent/disabling.

RESULTS

Thirteen of 23 patients (57%) had a total of 30 neurologic events. Eight patients (35%) had 18 TIAs. Eight patients (35%) also had a stroke, either CVA (n = 5, 22%) or ICB (n = 3, 13%), and 5 of these patients (22%) also had 12 TIAs. Three patients (13%) had 4 "other" neurologic events. Ten patients (43%) had transient/reversible neurologic deficits and 10 (43%) had permanent/disabling events. One patient (4%) had intracranial bleeding as a primary cause of death (anti-coagulation-related hemorrhage). The combined incidence of neurologic events was 1.37 events/patient-year. The incidences of transient and permanent events were 0.91 and 0.46 event/patient-year, respectively.

CONCLUSIONS

Neurologic events caused morbidity in the CUBS trial, with infrequent mortality. These results are similar to previous experiences with destination therapy and underscore the need for improvements in LVAD design, patient selection and patient management to reduce the incidence of neurologic events.

Report of the First U.S. Patient Successfully Supported Long Term With the LionHeart Completely Implantable Left Ventricular Assist Device System

We report our first successful long-term survivor in the United States with the LionHeart (Arrow International, Inc., Reading, PA) completely implantable left ventricular assist device system. The patient was initially deemed a poor candidate for cardiac transplantation and had inotrope-dependent, end-stage cardiac failure. The patient was supported for 13 months with this system. During this period of support, the patient returned to independent living and derived obvious benefits toward his daily activities with the completely implanted system. The device proved to be reliable during this period of support. Through lifestyle modification, the patient was ultimately deemed an appropriate candidate for heart transplantation and ultimately received successful transplantation.

Preoperative Pulmonary Hypertension Is Associated with Postoperative Left Ventricular Dysfunction in Chronic Organic Mitral Regurgitation: An Echocardiographic and Hemodynamic Study

BACKGROUND

Some degree of pulmonary hypertension (PHTN) is common in patients with chronic mitral regurgitation. The aim of this study was to determine whether preoperative PHTN is associated with postoperative left ventricular (LV) dysfunction.

METHODS

The study included 79 patients with chronic organic mitral regurgitation. Preoperative and postoperative LV function was assessed by echocardiography. Preoperative and postoperative hemodynamics were evaluated by a pulmonary artery catheter.

RESULTS

Pulmonary artery systolic pressure decreased postoperatively (pre 49 +/- 14 vs. post 36 +/- 11 mm Hg, P < .01). Postoperative LV ejection fraction was significantly reduced in patients with preoperative PHTN (pre 61 +/- 11% vs post 49 +/- 12%, P < .01). A stepwise multivariate regression analysis showed that preoperative pulmonary artery systolic pressure and LV end-systolic dimension were independent predictors of postoperative LV ejection fraction (r = -0.53, P < .001, and r = -0.34, P < .05, respectively).

CONCLUSION

Preoperative PHTN is associated with postoperative LV dysfunction in patients with chronic organic mitral regurgitation undergoing mitral valve operation.

Microtextured Materials for Circulatory Support Devices: Preliminary Studies

Thromboembolic events (TE) associated with circulatory support devices are a major source of mortality and morbidity. Clinically, the lowest TE rates are claimed with devices that incorporate textured blood-contacting materials. The textured materials currently used in circulatory assist devices are composed of small, attached fibers that form the boundaries of connected cavities. These cavities entrap blood components to form a "neointimal" layer, which is believed to minimize thromboembolic events. We believe that the three-dimensional surface topography of blood-contacting materials is a major controlling factor in the formation of a stable neointimal layer upon the material. Particle-cast cavities were used to form geometric features in segmented polyurethane. This microtextured material was incorporated as part of a flexible blood-contacting surface in a blood pump that was implanted as a left ventricular assist device in calves. The structure, thickness, stability, and development of the neointimal layer were then evaluated. These preliminary studies have shown that a stable neointimal layer can be formed upon the particle-cast surfaces. The results also indicate that the cavity size on the particle-cast surfaces has a significant effect on neointimal adhesion. The methods employed can be used in the design of future circulatory support devices.

Preliminary experience with the LionHeart left ventricular assist device in patients with end-stage heart failure

BACKGROUND

The Arrow LionHeart LVD 2000 left ventricular assist device is the first fully implantable system designed for destination therapy. We report on 2 years of experience with this device, which we implanted for the first time in October 1999.

METHODS

Since October 1999, 6 male patients between 55 and 69 years of age (mean 65 +/- 6 years) have received the device at our center; all were in New York Heart Association functional class IV and ineligible for heart transplantation.

RESULTS

All surgical procedures were uneventful, with a timely extubation in 5 of 6 patients. Duration of support was 17 to 670 (mean 245 +/- 138) days, with a cumulative experience of 4.5 years. Three patients recovered to be discharged from hospital under support and are long-term survivors. Three patients died 17, 31, and 112 days after implantation from multiple organ failure without being discharged to their homes. The survival rate is 50% after 18 months. There were no major system-related problems or any device-related infections, which are otherwise commonly found among vertricular assist device patients.

CONCLUSIONS

Our preliminary experience demonstrates the reliability and efficacy of the different parts of the system. Nevertheless, further sophistication is needed to reduce the size of its components, which so far still constitutes a limiting factor.

Detection of Björk-Shiley convexo-concave heart valve outlet strut single leg separations: consensus image acquisition and interpretation using two different cineradiographic imaging technologies

BACKGROUND

Conventional cineradiology has been used clinically to detect partially broken outlet struts (single leg separations, SLSs) in normally functioning Björk-Shiley convexo-concave (C/C) heart valves. The value of radiographic screening has, however, been debated in the medical literature. This study uses the same radiographic technique in sheep implanted with known-status C/C valves in combination with a newly developed geometric image magnification radiography system. This study was designed to test whether sensitivity and specificity of radiographic screening of C/C valves in detecting SLSs could be improved through the combination of readers and imaging modalities.

METHODS

Twenty-one sheep with mitral C/C valves were studied on both systems. Five were used for extensive scanning training. When operators were expert on both systems, 16 blinded study valves (4 intact and 12 with outlet strut SLSs) were scanned twice on both systems, first on a modified conventional and then a prototype geometric image magnification (Feinfocus(TM)) cineradiographic system by two expert physicians working together.

RESULTS

Among the 32 scanned valves, the two combined expert physicians were required to evaluate 40 intact legs and 24 with an SLS. For all SLS valves, the conventional and Feinfocus systems separately detected 50 (12/24) and 54% (13/24), respectively. When the two systems were combined, the final consensus score was correct in 67% (16/24) of all SLS valves.

CONCLUSIONS

Combined modality, paired expert physicians detected 67% of all SLSs. The Feinfocus system might be best reserved for those patients in whom the Siemens screening study demonstrates in minimally suspicious (grade 2) or suspicious (grade 3) appearance of a C/C valve outlet strut leg.

Database: relevant or not

Progress in the field of ventricular assist devices requires a more rigorous and systematic method of collecting outcomes data. A worldwide registry of device implants and results is proposed. With widespread participation, data from this registry would improve the identification of risk factors and complications, and allow for the creation of predictive models that would enhance patient selection. Professional societies should lead the development of a registry in close partnership with government and industry. Data collection using the Web, with rigorous security measures to protect patient privacy, would offer numerous advantages in efficiency and immediacy of communication for all participants.

The LionHeart LVD-2000: a completely implanted left ventricular assist device for chronic circulatory support

Management of patients with end-stage cardiac disease remains a vexing problem. Limitations in medical management and a fixed supply of donor organs for cardiac transplant have a continued impact on this growing population of patients. Mechanical circulatory support has proved very successful as a means of bridging patients to cardiac transplant when all medical options have been exhausted. The development of a chronic system of circulatory support has been underway at the Pennsylvania State University for nearly 30 years. These efforts have been recently merged with the industrial partnership with Arrow International toward the development of the LionHeart LVD-2000 (Arrow International, Reading, PA) completely implanted left ventricular support system. We present an overview of the system, details of implantation, a review of preclinical studies, and a synopsis of the first European implants. Early results have demonstrated the system to be safe, effective, and reliable. Transcutaneous energy transmission and the compliance chamber have been validated.

Modifications in surgical implantation of the Penn State electric total artificial heart

BACKGROUND

Two modifications of the surgical implantation protocol for the Penn State Total Artificial Heart (ETAH) were evaluated: Phrenic nerve ischemia was prevented by minimizing dissection and traction; and hemostasis was augmented and ETAH cuff anastomoses reinforced by using fibrin glue.

METHODS

Thirteen Holstein calves underwent orthotopic surgical implantation of the Penn State ETAH between February 1998 and August 2000. Mean hemodynamic and laboratory chemistry variables from the first postoperative week were compared between calves receiving the original (n = 7) and modified (n = 6) protocol.

RESULTS

Calves assigned to the modified protocol displayed an improvement in the Po2/FiO2 ratio compared to original (419.4 +/- 17.5 vs 336.3 +/- 35.4, respectively; p = 0.05). All additional parameters were equivalent between groups. The percent survival of animals receiving the modified protocol at 2, 4, and 12 weeks was higher than that of animals that underwent the original protocol. Original-protocol calf deaths consisting of hemothorax (n = 3), and respiratory failure (n = 1) were prevented in the modified protocol.

CONCLUSIONS

Our results suggest that manipulations in surgical protocol may promote increased survival in calves implanted with the Penn State ETAH.

Testing of a 50 cc stroke volume completely implantable artificial heart: expanding chronic mechanical circulatory support to women, adolescents, and small stature men

The development of a completely implanted total artificial heart at our institution has progressed to successful in vivo and in vitro testing of a device that is nearing clinical testing. This system consists of a 70 cc stroke volume pump originally designed to be used in men of average stature. Implantation of this system remains limited by patient size; hence, many women and adolescent patients will likely be precluded from support because of their smaller stature. A system similar in design, but with a 50 cc stroke volume pump has been developed. The first in vivo study of this device has been undertaken. A calf was supported for 33 days. The animal was extubated and ambulatory within the first 6 hours of implantation, and remained healthy until the thirty-third postoperative day when it suffered an embolic neurologic event. The pump and operating system worked flawlessly throughout the period of support. Further in vivo and in vitro testing will be undertaken. Development of a scaled down total artificial heart system expands this type of circulatory support to those critically ill patients previously deemed poor candidates because of their smaller body habitus.

Reoperation for a type I aortic dissection: case report

Surgery for the repair of a type I aortic dissection presents several difficulties for the surgeon and the perfusionist. One must safely support the patient, while at the same time provide the surgeon with a bloodless field in which to operate. Often, this requires cessation of the circulation for varying amounts of time. Deep hypothermia allows for an extension of the arrest period, while other techniques-- retrograde cerebral perfusion and antegrade cerebral perfusion--provide an additional degree of cerebral protection. Recently, we utilized these techniques concurrently on a 43-year-old female who presented for a reoperation for a type I aortic dissection. Combining these techniques allowed us to adequately support the patient during an anticipated lengthy period of circulatory arrest and insured a successful operation without any adverse cerebral or other organ dysfunction.

Complete radical nephrectomy and vena caval thrombectomy during circulatory arrest

PURPOSE

A modification of radical nephrectomy for renal carcinoma and vena caval tumor thrombectomy for supradiaphragmatic tumor extension under hypothermic circulatory arrest is presented.

MATERIALS AND METHODS

Nephrectomy was performed during the circulatory arrest time in 16 consecutive patients during the last 4 years.

RESULTS

Average hypothermic circulatory arrest time increased by 6 minutes. By elimination of manipulation of tumor and thrombus before circulatory arrest potential thrombus fragmentation and embolization were minimized. There were no significant differences in blood loss or complications compared to a prior series of 10 patients undergoing the procedure using conventional techniques.

CONCLUSIONS

Performance of complete radical nephrectomy along with venal caval embolectomy during circulatory arrest increases the safety of the procedure without significant morbidity.

Bridge to transplantation: the Penn State experience

BACKGROUND

During the past decade, ventricular assist devices as a bridge to transplantation have moved from the experimental arena to accepted therapy. Our institution has been at the forefront of the development of this technology and consequently has had extensive experience with the devices that are currently approved by the Food and Drug Administration for use as a bridge to heart transplantation.

METHODS

The successful management of patients with assist devices hinges on patient and device selection as well as perioperative management strategies. The routine use of agents such as aprotinin, vasopressin, milrinone, and inhaled nitric oxide has contributed to successful management of these patients. We present our perspectives on the advantages and disadvantages of the Thermo-Cardiosystems HeartMate 1000 IP device and the Thoratec (Pierce-Donachy) system. We also discuss our protocols and methods for patient selection, preoperative preparation, intraoperative strategy, and postoperative management that have resulted in improved patient outcomes.

RESULTS

More than 60 device implantation procedures have been performed since the inception of our bridge to transplantation program. During this time, two thirds of our patients were successfully bridged to transplantation. Of these patients, 92% were alive at 1 month after transplantation, and 83% were alive at 1 year after transplantation.

CONCLUSIONS

Both support systems are effective in supporting patients to heart transplantation. We have developed a preference for the Thermo-Cardiosystems HeartMate 1000 IP device because of its portability and associated better quality of life. However, the Thoratec device is the more versatile device, and circumstances exist when its use is clearly advantageous. In our institutional experience, outcome for bridging to transplantation has not been device dependent.

Application of retrograde cerebral perfusion and moderate systemic hypothermic circulatory arrest for cavoatrial tumor resection

Renal tumors invading the inferior vena cava have proved to be surgically challenging. For suprahepatic and right atrial involvement, deep hypothermic circulatory arrest (HCA) has been the favored procedure. Retrograde cerebral perfusion (RCP) was combined with moderate HCA in an effort to improve cerebral protection and avoid neurological sequelae. Six patients (mean age 64.7 years) who were operated on using this technique underwent a retrospective medical record analysis. The six patients achieved a mean cardiopulmonary bypass, HCA, and RCP time of 2 hours 34 minutes, 26.5 minutes, and 22 minutes, respectively. There were no focal cerebral defects or mortalities. Transient cerebral events were avoided compared to previous patients subjected to deeper hypothermia. All patients are living with no evidence of cancer 16-30 months after surgery. The addition of RCP to HCA for resection of supradiaphragmatic renal carcinoma enhances cerebral protection and allows time for a more efficacious operative procedure.

Steady state hemodynamic and energetic characterization of the Penn State/3M Health Care Total Artificial Heart

Total Artificial Heart (TAH) development at Penn State University and 3M Health Care has progressed from design improvements and manufacturing documentation to in vitro and in vivo testing to characterize the system's hemodynamic response and energetic performance. The TAH system is completely implantable and intended for use as an alternative to transplantation. It includes a dual pusher plate pump and rollerscrew actuator, welded electronics and battery assembly, transcutaneous energy transmission system, telemetry, and a compliance chamber. In vitro testing was conducted on a Penn State mock circulatory loop with glycerol/water solution at body temperature. Tests were performed to characterize the preload and afterload response, left atrial pressure control, and power consumption. A sensitive preload response was demonstrated with left atrial pressure safely maintained at less than 15 mm Hg for flow rates up to 7.5 L/min. Variations in aortic pressure and pulmonary vascular resistance were found to have minimal effects on the preload sensitivity and left atrial pressure control. In vivo testing of the completely implanted system in its final configuration was carried out in two acute studies using implanted temperature sensors mounted on the electronics, motor, and energy transmission coil in contact with adjacent tissue. The mean temperature at the device-tissue interface was less than 4 degrees C above core temperature.

Ventriculoarterial coupling with intra-aortic balloon pump in acute ischemic heart failure

PURPOSE

We analyzed the mechanism of effects of intra-aortic balloon pumping using the pressure-volume relationship and ventriculoarterial coupling in the normal and failing hearts.

MATERIALS

In 12 anesthetized Holstein calves (weight, 94 +/- 8 kg), the ventricular end-systolic and arterial elastances, pressure-volume area, and external work were analyzed during steady-state contractions with traditional hemodynamic parameters with intra-aortic balloon pumping-off and -on (1:1 synchronous ratio). An acute ischemic heart failure was induced by injecting 10 microm microspheres (4.2 +/- 1.8 x 10(7). 100g left ventricular weight-1) into the left main coronary artery; all measurements were repeated.

RESULTS

Intra-aortic balloon pumping did not change hemodynamic parameters in the control. However, during heart failure, intra-aortic balloon pumping decreased the arterial elastance from 3.6 +/- 1.3 mm Hg to 2.9 +/- 1.2 mm Hg. mL-1 while not affecting the ventricular end-systolic elastance, this resulted in an improvement of the ventriculoarterial coupling ratio from 3.1 +/- 0.8 to 2.3 +/- 0.8. Intra-aortic balloon pumping decreased not only end-systolic pressure (from 69 +/- 16 mm Hg to 64 +/- 19 mm Hg) but end-diastolic volume and pressure (from 139 +/- 38 mL to 137 +/- 37 mL and from 13. 9 mm Hg to 12.8 mm Hg, respectively) with the leftward shift of the pressure-volume loop. Pressure-volume area decreased (from 914 +/- 284 mm Hg to 849 +/- 278 mm Hg. mL) although stroke volume increased (from 21 +/- 6 mL to 24 +/- 6 mL).

CONCLUSION

Reduction of the arterial elastance with intra-aortic balloon pumping improved the ventriculoarterial coupling ratio and increased stroke volume. Leftward shift of the pressure-volume loop resulted in the reduction of pressure-volume area, which suggests the conservation of the myocardial oxygen consumption.

In vivo accuracy of two radiographic systems in the detection of Björk-Shiley convexo-concave heart valve outlet strut single leg separations

OBJECTIVE

Modified cineradiographic systems have been used clinically to detect partially broken outlet struts in normally functioning Björk-Shiley convexo-concave heart valves. Almost all such valves were explanted, presuming that full failure would likely follow. Inasmuch as the clinical setting only rarely permits examination of normally rated valves, the accuracy of radiographic detection cannot be clinically defined. This study uses the clinical radiographic technique in sheep implanted with known-status convexo-concave valves, comparing its accuracy and that of a newly developed, geometric image magnification radiography system.

METHODS

Twenty-one sheep with mitral convexo-concave valves were studied on both systems. Five were used for extensive training. When operators were expert with both systems, images of four intact valves and 12 valves with outlet strut single leg separations, along with a seventeenth single leg separation valve used for calibration, were integrated into 112 image sets organized into a balanced incomplete block design for evaluation by eight trained, blinded reviewers.

RESULTS

Cineradiography sensitivity was 24% versus 31% for direct image magnification. The odds ratio for detection of single leg separation by direct image magnification versus cineradiography was 2.0 (95% confidence interval, 0.76 to 5.9; p = 0.13). Cineradiography specificity was 93% versus 90% for direct image magnification. Sensitivity and specificity varied markedly by reviewer, with sensitivity ranging from 8% to 55% and specificity from 51% to 100% for the combined technologies.

CONCLUSIONS

The data support the need for more intensive training for convexo-concave valve imaging and further investigation of unconventional radiographic technologies. Clinical cineradiography of convexo-concave valves may detect as little as 25% of valves having a single leg separation, underestimating the prevalence of single leg separations and thereby implying more rapid progression to full fracture than is actually the case.

Radiographic detection of single-leg fracture in Björk-Shiley Convexo-Concave prosthetic valves: a phantom model study

Cineradiography can identify patients with single-leg fractured Björk-Shiley Convexo-Concave valves, although little is known about the sensitivity and specificity of this technique. We evaluated three normal and six (0 microm gap) single-leg fractured Björk-Shiley valves that were placed in a working phantom model. Valves were randomly imaged a total of 33 times and duplicated into a 120-valve series with a 1:9 ratio of abnormal/normal valves. Six reviewers independently graded each valve and demonstrated markedly different rates of identifying the fractured valves. Average sensitivity at the grade that clinically results in valve explanation was 47%. Among the normal valves, a correct identification was made 96% (range 91% to 99%) of the time. Present radiographic technology may have significant difficulty in identifying true single-leg fracture in Björk-Shiley valves with limb separations that are common among clinically explanted valves.

Data quality review program: the Society of Thoracic Surgeons Adult Cardiac National Database

In summary, the National Database Committee's Audit and Validation Subcommittee is working to maximize the data completeness and quality of the STS National Database. Toward this end, we welcome your suggestions for improvement.

In vivo observation of cavitation on prosthetic heart valves

In this study, a method to determine the existence of prosthetic heart valve cavitation in vivo is presented. Pennsylvania State University Left Ventricular Assist Devices (LVADs) were implanted in two separate calves for this study. Björk-Shiley Monostrut (Irvine, CA) 27 mm and 25 mm valves with Delrin occluders were used in the mitral and aortic positions, respectively. A high fidelity, piezoelectric pressure transducer was mounted approximately 1.25 cm proximal to the mitral valve and measured the high frequency pressure fluctuations caused by cavitation bubble formation and collapse after valve closure. The root mean square (RMS) value of the mitral pressure signal during a 5 ms interval after valve closure was used as a measure of cavitation intensity. The pressure signals observed in vivo were similar to ones observed in vitro with the same type of pressure transducer and were associated with the visually observed cavitation. The percentage of beats with cavitation increased from 20.3% to 67.7% when pump filling was decreased by increasing beat rate. A blood test conducted during post-operative days 1-3 showed a significant increase in plasma hemoglobin during the low filling condition. However, blood tests conducted later (post-operative days 7-44) did not show a significant change in plasma hemoglobin during low filling conditions.

Bridging to transplant. Equal extended survival for patients undergoing LVAD support when compared with long-term medical management

Implantation of ventricular assist devices (VADs) to support patients awaiting cardiac transplant has become an effective means of assuring that these critically ill patients survive to transplant. The authors undertook a retrospective analysis of 115 consecutive patients listed for cardiac transplant from January 1992 through June 1995. A VAD was implanted in 19 of these patients. Survival was calculated by intent to treat from the time of transplant listing through heart transplant, if it occurred. The analysis demonstrates that the patients who underwent implantation of a VAD as bridge to transplant had survival times similar to those of patients with medical management. These survival statistics demonstrate the utility of VADs as an effective means to bridge critically ill patients until a suitable donor organ becomes available. In addition, as previous studies have suggested for acute results, earlier implementation and better patient selection may lead to improved long-term survival.

Results of mechanical ventricular assistance for the treatment of post cardiotomy cardiogenic shock

The voluntary submission of data on patients who receive mechanical circulatory assistance for post cardiotomy cardiogenic shock and acute myocardial infarction has resulted in an established data base for the ongoing evaluation of these devices. Since its inception in 1985, there have been 1,279 cases reported of implanted ventricular assist devices for post cardiotomy cardiogenic shock. The average duration of support for these devices is approximately 4 days. Those patients who underwent implantation of a centrifugal pump had significantly shorter periods of support when compared with the pneumatically supported group. Patients had similar periods of support when comparing clinical outcome. Approximately 70% of the reported cases underwent centrifugal assistance. The majority of reported cases were supported with isolated left ventricular assistance. There was no significant difference in overall outcome statistics when comparing type or mode of support. Approximately 45% of reported patients were weaned from circulatory assistance, and 25% of all patients survived to discharge. These numbers remain consistent with previously reported statistics. The results with acute myocardial infarction remain limited. Of the 96 reported patients, 26% were weaned from support and only 11.5% survived to discharge. This report continues to support the use and research for advancement of these devices toward the treatment of post cardiotomy cardiogenic shock.