Biomedical subjects

Jose L Navia

Publications and source records attributed to Jose L Navia.

16 recordsLinked to original sources

PubMed2006

Ventricular assist devices and aggressive immunosuppression: looking beyond overall survival.

BACKGROUND: Patients bridged to heart transplantation with a ventricular assist device (VAD) developed coronary vasculopathy at the same rate as non-bridged patients despite having higher levels of pre-formed antibodies. We hypothesized that allosensitized VAD patients have higher levels of immunosuppression and thus different morbidity and causes of mortality. METHODS: Patients who received a transplant between January 1996 and May 2002 were separated into 2 groups based on the need for VAD support as a bridge to transplantation. Transplant and Inpatient Pharmacy Databases and charts were queried for date of transplantation, degree of allosensitization, use of desensitization therapy, immunosuppressive strategies, number of treated rejection episodes, and specific causes of death. RESULTS: This study investigated 238 patients (125 VAD patients, 113 non-VAD patients). VAD patients were more likely to be allosensitized than non-VAD patients (20% vs 5%, p < 0.01). OKT3 was given to 22% of VAD patients as anti-rejection prophylaxis and 14% received pre-transplant plasmapheresis. Non-VAD patients rarely were desensitized (2.6% of non-VAD patients). After transplantation, 68 VAD patients (54%) and 44 non-VAD patients (39%) had episodes of severe rejection requiring therapy. Episodes of rejection in VAD patients were commonly treated with steroids (90%), plasmapheresis (10%), and OKT3 (7%), and episodes of rejection in non-VAD patients were treated with steroids (76%) and OKT3 (8%). The 5-year survival for both groups was similar (90% and 86% respectively, p = 0.31). VAD patients commonly died of sepsis (75%), and non-VAD patients died of rejection (39%) and ischemic transplant cardiomyopathy (30%). CONCLUSION: When short-term outcomes between bridged and non-bridged heart transplant recipients were compared, overall survival was similar but causes of death differed. Findings in this study might aid in the post-operative management of patients bridged to transplantation with a VAD.

Aged↗

PubMed2006

Surgery for permanent atrial fibrillation: impact of patient factors and lesion set.

BACKGROUND: Whether a complete Cox-maze procedure is needed to ablate permanent atrial fibrillation in patients undergoing concomitant cardiac surgery is unknown. Our objective was to assess the effectiveness of different lesion sets in such patients. METHODS: From November 1991 to January 2004, 575 patients underwent surgical treatment of permanent atrial fibrillation (duration > 6 months); mitral valve disease was the primary indication for surgery in 74%. Procedures included pulmonary vein isolation alone (n = 68, 12%), pulmonary vein isolation with left atrial connecting lesions (n = 265, 46%), and Cox-maze (n = 242, 42%). Rhythm documented on 5,120 postoperative electrocardiograms was used to estimate time-related prevalence of, and risk factors for, atrial fibrillation. RESULTS: Prevalence of postoperative atrial fibrillation peaked at 46% two weeks after operation, declining to 24% at one year. Patient-related risk factors for increased prevalence included older age (p < 0.0001), larger left atrium (p < 0.0001), and longer duration of preoperative atrial fibrillation (p = 0.0008). The Cox-maze procedure and lesion sets resembling it created with alternative energy sources had a similarly low prevalence of late postoperative atrial fibrillation; in contrast, pulmonary vein isolation and lesion sets that did not include a lesion to the mitral anulus were less effective. CONCLUSIONS: This study suggests that in cardiac surgical patients with permanent atrial fibrillation the left atrial lesion set should include wide pulmonary vein isolation, at least one connection between right and left pulmonary veins, and a connection to the mitral anulus. Availability of alternative energy sources to create lesions sets has virtually eliminated the need for the cut-and-sew Cox-maze procedure.

Adult↗

PubMed2006

Duration of inotropic support after left ventricular assist device implantation: risk factors and impact on outcome.

OBJECTIVES: Because duration of inotropic support after left ventricular assist device implantation has been recognized as a surrogate for right ventricular dysfunction, we sought to (1) identify its preimplantation risk factors, particularly its association with preimplantation right ventricular dysfunction, and (2) assess its impact on clinical outcomes. METHODS: Between 1991 and 2002, left ventricular assist devices were implanted in 207 patients, exclusive of those receiving preoperative mechanical circulatory support, which precluded measuring right ventricular stroke work. Duration of inotropic support was analyzed as a continuous variable, truncated by death or transplantation, and in turn as a risk factor for these 2 events. RESULTS: Inotropic support decreased from 100% on the day of implantation to 57%, 33%, and 22% by days 7, 14, and 21. Its duration was strongly associated with lower preimplantation right ventricular stroke work index, older age, and nonischemic cardiomyopathy and was associated (P < .04) with higher mortality before transplantation but not with transition to transplantation. We identified no preimplantation risk factors for right ventricular assist device use because of its relatively infrequent use in this population (18 patients, only 4 of whom survived to transplantation). CONCLUSION: Duration of inotropic support after left ventricular assist device insertion is strongly correlated with low preimplantation right ventricular stroke work index. In turn, it was associated with reduced survival to transplantation. Thus, right ventricular stroke work measured before implantation might be useful in decision making for biventricular support, destination therapy, or total artificial heart.

Cardiomyopathies↗

PubMed2006

Surgical treatment of pseudoaneurysm of the thoracic aorta.

OBJECTIVES: To examine the clinical profiles, operative outcomes, and late results of patients with pseudoaneurysm of the thoracic aorta. METHODS: From 1990 to 2002, 60 patients underwent repair of aortic pseudoaneurysm: ascending aorta in 70%, ascending aorta and arch in 15%, descending aorta in 10%, and arch alone in 5%. Mean age was 53 +/- 15 years, and 70% were men. Of these, 50 (83%) had undergone previous cardiac surgery, including 22 (37%) composite valve graft operations. The preferred cannulation site was femoral-femoral (n = 27, 45%), with deep hypothermic circulatory arrest in 62% and retrograde cerebral perfusion in 33%; more recently, however, axillary cannulation has been preferred. RESULTS: Principal etiologies were graft infection in ascending aorta pseudoaneurysm and trauma in descending aorta pseudoaneurysm. Fifteen patients (25%) presented with chest pain, 13 (22%) with heart failure, and 20% with moderate or severe aortic regurgitation. The pseudoaneurysm was resected and the aorta replaced (n = 45, 75%) or repaired (n = 15, 25%) using various methods. Hospital mortality was 6.7% (n = 4). Reexploration for bleeding was required in 8.3%, and 3.3% had postoperative stroke. At 30 days, 5 years, and 10 years, survival was 94%, 74%, and 60% and freedom from reoperation was 95%, 77%, and 67%, respectively. CONCLUSIONS: Most patients with aortic pseudoaneurysm require ascending aorta and/or arch replacement, which can be accomplished with low operative mortality and morbidity. Long-term survival and freedom from reoperation in these young patients parallel those expected for complex cardiac and aortic disease.

Adult↗

PubMed2005

The Cox maze procedure in mitral valve disease: predictors of recurrent atrial fibrillation.

OBJECTIVES: The Cox maze procedure is the gold standard for ablation of atrial fibrillation in patients undergoing mitral valve surgery, and new approaches to atrial fibrillation ablation must be compared with it. Therefore, we sought to determine the time-related prevalence of atrial fibrillation and its risk factors after combined Cox maze and mitral valve surgery. METHODS: From November 1991 through January 2004, 263 patients (mean left atrial diameter, 5.8 +/- 1.2 cm) underwent combined mitral valve surgery (repair in 71%) and a cut-and-sew Cox maze procedure for atrial fibrillation (permanent, 74%; persistent, 7%; paroxysmal, 16%). Rhythm documented on 2367 postoperative electrocardiograms was used to estimate the prevalence of atrial fibrillation across time. RESULTS: Hospital mortality was 1.9%. Postoperative atrial fibrillation prevalence peaked at 36% at 2 weeks, decreasing to 21% at 5 years. Risk factors for higher postoperative atrial fibrillation prevalence varied with time and included longer duration of preoperative atrial fibrillation (P = .003), larger left atrial diameter (P = .01), older age (P = .0002), and higher left ventricular mass index (P = .02). CONCLUSIONS: In some patients undergoing mitral valve surgery and a Cox maze procedure, atrial fibrillation recurs over time, mandating close, long-term follow-up of heart rhythm. Earlier operation and left atrial size reduction should be considered to improve results in selected patients.

Atrial Fibrillation↗

PubMed2005

Early and midterm risk of coronary allograft vasculopathy in patients bridged to orthotopic heart transplantation with ventricular assist devices.

BACKGROUND: Coronary transplant vasculopathy (CAV) has been associated with both immunologic and nonimmunologic factors. The impact of preoperative ventricular assist device (VAD) support on the development of CAV has not been studied. To examine this, we obtained posttransplant coronary angiograms from a group of patients bridged with VAD and compared them to post transplant coronary angiograms of a non-VAD cohort. METHODS: Adult patients undergoing orthotopic heart transplant between 1996-2000 were retrospectively studied and divided into VAD and non-VAD patients. Coronary angiograms were retrospectively reviewed and severity of coronary vasculopathy was categorized as trivial, mild, moderate, or severe. Other variables studied included recipient and donor demographics, cytotoxic panel reactive antibodies (PRA) against T-cell targets and flow cytometric crossmatching against donor T lymphocytes. RESULTS: There was no significant difference between groups regarding demographics. However, VAD patients had a sixfold greater chance of having a T-cell PRA >10% at the time of transplant (p < 0.05), and a fourfold greater chance of having a positive cross match when compared to non-VAD patients (p < 0.05). There was no significant difference in the degree of CAV between groups. Normal coronary anatomy was present in 76% of VAD patients and 64% of non-VAD patients (p = 0.37). These results were similar at 2- and 3-year follow-up (76 vs. 74% and 80 vs. 62%, respectively). CONCLUSION: Preoperative VAD use is associated with increased sensitization; however, these patients develop CAV at the same rate as those not bridged with a VAD.

B-Lymphocytes↗

PubMed2005

Combined minimally invasive pulmonary vein isolation, left atrial appendage excision and cardiac resynchronization therapy for heart failure: case report.

A 76-year-old male with ischemic cardiomyopathy presented with heart failure symptoms in the absence of angina. Several hospitalizations were required due to heart failure exacerbation and paroxysmal atrial fibrillation. Electrocardiography and tissue synchronization imaging confirmed ventricular dyssynchrony, requiring biventricular pacing. After a failed attempt of percutaneous placement of the left ventricular lead, a novel minimally invasive approach was indicated. It consisted of left ventricular epicardial lead placement, microwave pulmonary vein isolation, and left atrial appendage excision through bilateral minithoracotomies. The postoperative recovery was unremarkable, with reestablishment of the ventricular synchrony and regular rhythm.

Aged↗

PubMed2004

Preload-adjusted right ventricular maximal power: concept and validation.

Right ventricular (RV) maximal power (PWR(mx)) is dependent on preload. The objective of this study was to test our hypothesis that the PWR(mx) versus end-diastolic volume (EDV) relationship, analogous to the load-independent stroke work (SW) versus EDV relationship (preload-recruitable SW, PRSW), is linear, with the PWR x-axis intercept (V(0PWR)) corresponding to the PRSW intercept (V(0SW)). If our hypothesis is correct, the preload sensitivity of PWR(mx) could be eliminated by adjusting for EDV and V(0PWR). Ten dogs were instrumented with a pulmonary flow probe, micromanometers, and RV conductance catheter. Data were obtained during bicaval occlusions under various conditions and fitted to PWR(mx) = a.(EDV - V(0PWR))(beta), where a is the slope of the relationship. The PWR(mx) versus EDV relationship did not deviate from linearity (beta = 1.09, P = not significant vs. 1), and V(0PWR) correlated with V(0SW) (r = 0.93, P <0.0001). V(0PRW) was related to steady-state EDV and left ventricular end-diastolic pressure, allowing for estimation of V(0PWR) (V(0Est)) and single-beat PWR(mx) preload adjustment. Dividing PWR(mx) by the difference of EDV and V(0PWR) (PAMP(V0PWR)) eliminated preload dependency down to 50% of the baseline EDV. PWR(mx) adjustment using V(0Est) (PAMP(V0Est)) showed similar preload independency. Enhancing contractility increased PAMP(V0PWR) and PAMP(V0Est) from 176 +/- 52 to 394 +/- 205 W/ml x 10(4) and 145 +/- 51 to 404 +/- 261 W/ml x 10(4), respectively, accompanied by an increase of PRSW from 13.0 +/- 4.5 to 29.7 +/- 16.4 mmHg (all P <0.01). PAMP(V0PWR) and PAMP(V0Est) correlated with PRSW (r = 0.85; r = 0.77; both P <0.001). Numerical modeling confirmed the accuracy of our experimental data. Thus preload adjustment of PWR(mx) should consider a linear PWR(mx) versus EDV relationship with distinct V(0PWR). PAMP(V0PWR) is a preload-independent estimate of RV contractility that may eventually be determined noninvasively.

Animals↗

PubMed2004

Contemporary outcomes of outpatients referred for cardiac transplantation evaluation to a tertiary heart failure center: impact of surgical alternatives.

BACKGROUND: The growing epidemic of congestive heart failure in the setting of limited donor-organ availability has mandated continued development and increased utilization of medical and surgical alternatives to cardiac transplantation. We sought to assess current disposition and outcomes of patients recently referred for transplant evaluation to a single high-throughput tertiary referral center. METHODS AND RESULTS: We performed a retrospective observational review of consecutive patients with advanced heart failure who were assessed initially in an outpatient setting by a heart failure cardiologist, with a view to transplant or nontransplant surgical alternatives between 1995 and 2000. Of 1174 consecutive referrals (mean age 55.1 [+/-12.7], 74% male), 588 (50%) were recommended for medical treatment (mean age 55.3 [+/-12.4], 72% male) and 200 (17%) for nontransplant surgery, principally coronary artery bypass grafting, mitral valve repair, infarct exclusion, partial left ventriculectomy, or combinations thereof (mean age 57.8 [+/-10.6], 76% male). A minority, 418 (36%), were initially listed for cardiac transplantation (mean age 53.5 [+/-13.9], 80% male). Of these, 74 (18% of listed) died waiting (34 on left ventricular assist device support), 45 were delisted (27 for improved clinical status), and 217 (18% of referred group) have been transplanted. The 3-year survival (Kaplan-Meier) was equivalent (82%) in the transplanted and nontransplant surgery groups (excluding partial left ventriculectomy patients). CONCLUSION: In current clinical practice less than one fifth of transplant referrals are ultimately transplanted, reflecting both a limited donor supply and the application of alternative, nontransplant strategies. Medium-term survival in patients suitable for alternative surgical strategies equals that of cardiac transplantation.

Adult↗

PubMed2002

Predictors of severe right ventricular failure after implantable left ventricular assist device insertion: analysis of 245 patients.

BACKGROUND: Insertion of an implantable left ventricular assist device (LVAD) complicated by early right ventricular (RV) failure has a poor prognosis and is largely unpredictable. Prediction of RV failure after LVAD placement would lead to more precise patient selection and optimal device selection. METHODS AND RESULTS: We reviewed data from 245 patients (mean age, 54+/-11 years; 85% male) with 189 HeartMate (77%) and 56 Novacor (23%) LVADs. Ischemic cardiomyopathy predominated (65%), and 29% had dilated cardiomyopathy. Overall, RV assist device (RVAD) support was required after LVAD insertion for 23 patients (9%). We compared clinical and hemodynamic parameters before LVAD insertion between RVAD (n=23) and No-RVAD patients (n=222) to determine preoperative risk factors for severe RV failure. By univariate analysis, female gender, small body surface area, nonischemic etiology, preoperative mechanical ventilation, circulatory support before LVAD insertion, low mean and diastolic pulmonary artery pressures (PAPs), low RV stroke work (RVSW), and low RVSW index (RVSWI) were significantly associated with RVAD use. Elevated PAP and pulmonary vascular resistance were not risk factors. Risk factors by multivariable logistic regression were preoperative circulatory support (odds ratio [OR], 5.3), female gender (OR, 4.5), and nonischemic etiology (OR, 3.3). CONCLUSIONS: The need for circulatory support, female gender, and nonischemic etiology were the most significant predictors for RVAD use after LVAD insertion. Regarding hemodynamics, low PAP and low RVSWI, reflecting low RV contractility, were important parameters. This information may lead to better patient selection for isolated LVAD implantation.

Adolescent↗

PubMed2002

Do left ventricular assist device (LVAD) bridge-to-transplantation outcomes predict the results of permanent LVAD implantation?

BACKGROUND: Implantable left ventricular assist devices (LVADs) were designed for permanent implant, but we began their use for bridge-to-transplant (BTTx) to study their safety and effectiveness. We review our experience in order to compare the BTTx lessons learned with the outcomes and goals of permanent implants. METHODS: From December 1991 until January 2002, 264 patients received 277 LVADs for BTTx. We analyzed temporal trends in pre-LVAD patient factors and device-specific time-related complications. RESULTS: Survival to transplant was 69%. Adverse event analysis demonstrated a high risk of infections (0.56, 1.28, and 1.88 per patient at 30 days and 3 and 6 months). HeartMate devices were more prone to infection than Novacor devices (p < 0.0001). Cerebral infarctions occurred less commonly than infections (0.15, 0.25, 0.30 at 30 days and 3 and 6 months), were more common in Novacor than HeartMate (p = 0.0001), and were decreased by the new Novacor Vascutek conduit (p = 0.07), but these were still slightly higher than the HeartMate (p = 0.04). Device failures occurred in 21 instances (all but one were in HeartMate devices [p = 0.04 vs Novacor]), but have significantly decreased (p < 0.0001) in HeartMate since 1998. CONCLUSIONS: Infections and device durability limit the chronic use of the HeartMate device, but device failures are decreasing. Novacor has fewer problems with infection and durability, and the new Vascutek conduit will reduce, but not eliminate, strokes.

Cerebral Infarction↗

PubMedDate not supplied

Reduction of mitral regurgitation using the Coapsys device: a novel ex vivo method using excised recipients' hearts.

The purpose of this study was to evaluate the ex vivo effects of the Coapsys device upon functional mitral regurgitation (MR) in human hearts. We used seven excised hearts from patients who underwent cardiac transplantation. All patients had functional MR of grade 2 or greater associated with dilated (n = 3) or ischemic (n = 4) cardiomyopathy. After the aortic valve was removed, the left ventricle was pressurized from the aorta with saline at a constant pressure. The degree of MR was then subjectively graded from the opened left atrium (from 0 to 4). The last three studies included volumetric measurements of MR. By tightening the device, the mean MR grade was reduced from 3.3 +/- 0.8 to 1.1 +/- 0.4 (p = 0.0002). In the quantitative analysis, mean regurgitation volume was reduced from 1,108 +/- 1,134 ml/min to 236 +/- 89 ml/min (p = not significant). The mitral annular septal-lateral dimension decreased from 2.0 +/- 0.3 cm to 1.6 +/- 0.5 (p = 0.043). The Coapsys device reduced functional MR in the ex vivo study using excised dilated hearts.

Cardiomyopathy, Dilated↗

PubMedDate not supplied

In vitro performance of the novel coronary sinus AutoRetroPerfusion Cannula.

Myocardial salvage through coronary sinus intervention has been documented. The AutoRetroPerfusion Cannula is a novel device that is able to perfuse the coronary bed retrogradely through the coronary sinus with arterial blood generated from a peripheral artery with no need for a pump. The cannula consists of a distal end that, once secured in the coronary sinus, opens an umbrella-like membrane to create pressure in the coronary sinus, and at the same time has small channels directed backwards to the right atrium to provide pressure relief. The cannula is introduced from the axillary vein under local anesthesia and the proximal end, which consists of a graft, is anastomosed to the axillary artery to start autoperfusion once the distal end is secured in the coronary sinus and the occluding membrane is open. The AutoRetroPerfusion Cannula was tested in the in vitro mock loop under 50-120 mm Hg of proximal pressure and 50, 100, and 150 ml/min of total flow in the cannula. We were able to achieve the nominal design point of 40-80 mm Hg of distal pressure and 50-150 ml/min of distal flow by adjusting the number, diameter, and length of the small backwards channels.

Biomedical Engineering↗

PubMedDate not supplied

Regional referral system for patients with acute mechanical support: experience at the Cleveland Clinic Foundation.

Regional referral networks ("hub and spoke") have been created to facilitate the transfer of patients on mechanical circulatory support. Although individual centers report good success, overall outcomes have remained poor. We investigated whether preoperative variables influenced survival and could be used to help select patients best served by referral. A retrospective chart review was conducted on all patients transferred to our institution supported on cardiac assist devices. Between January 1995 and September 2003, 39 patients were received in transfer for continued care after the implantation of a cardiac assist device. Eighty-five percent of patients had the ABIOMED BVS 5000 implanted. The most common indication was postcardiotomy shock. Sixty-four percent of patients were not candidates for heart transplantation due to medical or social contraindications. The 30-day mortality of this group was 62%. Survivors had less comorbidity and were less likely to have complex surgeries, neurologic impairment, and multisystem organ failure when presenting to our center. Devices were weaned in 30% of cases. Only six patients (15%) were successfully transplanted, and five of these patients have done well at follow-up. Based on our experience, we believe that cardiogenic shock patients benefit from a regional referral system if they have not had complex cardiac surgical procedures or developed multisystem organ failure. Furthermore, there is a survival advantage when using long-term devices because this allows possible recovery or transplantation.

Adult↗

PubMedDate not supplied

Replacement of the left-side valves of an implanted total artificial heart.

The MagScrew total artificial heart (TAH) is under development. Despite its anticipated durability and reliability, the possibility of a bioprosthetic valve malfunction exists. As a result, the potential for valve replacement surgery, instead of device replacement, would be desirable after a TAH implant. In two of our 90-day animal experiments, we successfully replaced the left-side valves through a left thoracotomy opposite to the right-sided incision site for the initial TAH implant. The results of these cases suggest that the left-side valves could also be replaced through a left thoracotomy approach in humans. To confirm the ability to access the left-side valves in humans, four human cadaver studies were performed with the use of a mock pump designed for human application. This report describes the operative techniques for left-side valve replacement in animals and discusses the advantages of a left thoracotomy in clinical situations, based on results from the human cadaver studies.

Animals↗

PubMedDate not supplied

Solitary massive right ventricular metastasis of renal cell carcinoma without inferior vena cava or right atrium involvement.

Right ventricular metastases from renal cell carcinoma without inferior vena cava or right atrium involvement are rare. A 67-year-old male presented with hematuria and congestive heart failure. Computed tomography revealed a left renal mass. In addition, an intra-cardiac mass was found during the preoperative workup, causing right ventricular outflow tract obstruction. His past medical history included previous coronary bypass grafting. The patient underwent combined radical nephrectomy and removal of right ventricular mass. Pathology confirmed renal cell carcinoma with extensive sarcomatoid features in both the left kidney and right ventricle. His postoperative recovery was unremarkable.

Aged↗