Yuguo Weng

Long-Term Results in Patients With Idiopathic Dilated Cardiomyopathy After Weaning From Left Ventricular Assist Devices

Background—Since our first successful left ventricular assist device (LVAD) explantation in a patient with idiopathic dilated cardiomyopathy (IDCM) in 1995, an additional 31 IDCM patients have been weaned in our department. Echocardiographic evaluations during repeated “off-pump” trials were the cornerstone for weaning decisions. After 9 years of experience, we assessed the reliability of our weaning criteria in light of the long-term results. Methods and Results—We evaluated all of the IDCM patients who were weaned between March 1995 and March 2004 with regard to preservation of cardiac function without LVAD support and survival after weaning. Additionally, we reviewed our echocardiographic data to assess their predictive value for long-term stability of cardiac function after weaning. The 32 weaned IDCM patients showed a survival rate of 78.3%±8.1 at 5 years after LVAD explantation. Heart failure (HF) recurred during the first 3 years after weaning in 31.3%. Only 2 patients died because of HF after weaning; the other patients with HF recurrence were successfully transplanted. Off-pump LV end-diastolic diameter >55 mm and/or LVEF <45% before LVAD removal, as well as history of HF ≥5 years before LVAD implantation, appeared to be major risk factors for early recurrence of HF. Patients without any of these 3 risk factors showed no HF recurrence during the first 3 years after weaning, but at the same time, all of those with at least 2 of these 3 risk factors developed early recurrence of HF. In patients with HF recurrence during the first 3 postweaning years, a significant LVEF decrease already occurred during the first month after weaning, whereas in those with long-term stable cardiac function even at the end of the sixth postweaning month, the LVEF was not different from that before LVAD removal. Conclusions—For selected patients with IDCM, weaning from LVADs is a clinical option with good results over >9 years and should, therefore, be considered in those with cardiac recovery after LVAD implantation. Off-pump echocardiographic data are reliable for the detection of LV recovery and prediction of long-term cardiac stability after weaning.

Tricuspid Incompetence and Geometry of the Right Ventricle as Predictors of Right Ventricular Function After Implantation of a Left Ventricular Assist Device

BACKGROUND Implantation of a left ventricular assist device (LVAD) is an established treatment for end-stage heart failure. Right ventricular (RV) dysfunction develops in 20% to 50% of patients after LVAD implantation, leading to prolonged ICU stay and elevated mortality. However, the prediction of RV failure remains difficult. METHODS The pre-operative echocardiographic parameters, tricuspid incompetence (TI), RV end-diastolic diameter (cut-off >35 mm), RV ejection fraction (cut-off <30%), right atrial dimension (cut-off >50 mm) and short/long axis ratio (cut-off >0.6), were analyzed retrospectively in 54 patients. Patients were divided into two groups. One group consisted of patients with RV failure (n = 9), as defined by the presence of two of the following criteria in the first 48 hours after surgery: mean arterial pressure < or =55 mm Hg; central venous pressure > or =16 mm Hg; mixed venous saturation < or =55%; cardiac index 20 units; or need for an RVAD. The other patients comprised the non-RV-failure group (n = 45). RESULTS The RV failure group had a significantly higher short/long axis ratio of the RV (0.63 vs 0.52, p = 0.03; odds ratio 4.4, p = 0.011). For patients with a short/long axis ratio of the RV of <0.6, RV failure occurred in 7% of patients, as compared with 50% for patients with a ratio > or =0.6 (p = 0.013). Among patients with TI Grade III or IV, 75% developed RV failure as compared with 12% in patients with TI Grade I or II (p = 0.054). The odds ratio for RV failure after LVAD implantation for TI Grade III or IV was 4.7 (p = 0.012). CONCLUSIONS Pre-operative evaluation of tricuspid incompetence and RV geometry may help to select patients who would benefit from biventricular support.

Prediction of Cardiac Stability After Weaning From Left Ventricular Assist Devices in Patients With Idiopathic Dilated Cardiomyopathy

Background— During ventricular assist device (VAD) unloading, cardiac recovery is possible even in patients with chronic heart failure (HF). We sought parameters predictive of cardiac stability after VAD removal. Methods and Results— Among 81 patients weaned since March 1995, a homogenous group of 35 with idiopathic dilated cardiomyopathy weaned from left VADs was selected. We evaluated echo data obtained before left VAD implantation and during “off-pump” trials before explantation, histological changes, and serum anti-&bgr;1-adrenoceptor-autoantibody disappearance during unloading, duration of unloading, and HF duration. Postweaning 10-year survival with native hearts reached 70.7±9.2%. During the first 5 years, HF recurred in 13 patients (37.1%). Only 6 (17.1%) died after HF recurrence or noncardiac complications related to left VAD explantation. Comparison of patients with and without long-term cardiac stability showed that stable patients were younger, HF history and recovery time during unloading shorter, and preweaning left ventricular assessment revealed higher left ventricular ejection fraction, lower short/long axis ratios, and higher end diastolic relative wall thicknesses. For left ventricular ejection fraction ≥45% at end diastolic diameter of ≤55 mm, predictive value for ≥5-year cardiac stability was 87.5%. Left ventricular ejection fraction time course during the first 6 postweaning months appeared predictive for long-term stability. HF history >5 years and preweaning instability of cardiac improvement appeared predictive for HF recurrence. Conclusions— In idiopathic dilated cardiomyopathy, left VAD removal can be successful for >12 years even with incomplete cardiac recovery. Pre-explantation left ventricular ejection fraction, left ventricular end diastolic diameter and relative wall thicknesses, stability of unloading-induced cardiac recovery, duration of left VAD support, and HF duration before left VAD insertion allow identification of patients able to remain stable for >5 years. Time course of left ventricular ejection fraction during the first 6 postweaning months allows prognostic assessment.

Heart failure reversal by ventricular unloading in patients with chronic cardiomyopathy: criteria for weaning from ventricular assist devices

Aims Unloading-promoted reversal of heart failure (HF) allows long-term transplant-free outcome after ventricular assist device (VAD) removal. However, because few patients with chronic cardiomyopathy (CCM) were weaned from VADs (the majority only recently), the reliability of criteria used for weaning decisions to predict long-term post-weaning success is barely known. After 15 years of weaning experience, we assessed this issue. Methods and results In 47 patients with CCM as the underlying cause for HF, who were part of a total of 90 patients weaned from bridge-to-transplant-designed VADs since 1995, we analysed data on cardiac morphology and function collected before VAD implantation, echocardiographic parameters recorded during ‘off-pump’ trials, duration of HF before implantation, and stability of recovery before and early after VAD removal. Post-weaning 5 year freedom from HF recurrence reached 66%. Only five patients (10.6%) died due to HF recurrence or weaning-related complications. Pre-explantation off-pump left ventricular ejection fraction (LVEF) of ≥50 and ≥45% revealed predictive values for cardiac stability lasting ≥5 years after VAD removal of 91.7 and 79.1%, respectively. With each unit of LVEF reduction, the risk of HF recurrence became 1.5 times higher. The predictive value of LVEF ≥45% also became >90% if additional parameters like pre-explantation LV size and geometry, stability of unloading-induced cardiac improvement before VAD removal, and HF duration before VAD implantation were also considered. Definite cut-off values for certain parameters (including tissue-Doppler-derived LV wall motion velocity) allowed formulation of weaning criteria with high predictability for post-weaning stability, also in patients with incomplete cardiac recovery. Conclusions Ventricular assist device removal in CCM patients is feasible and can be successful even after incomplete cardiac recovery. Parameters of pre-explantation cardiac function, LV size and geometry, their stability during final off-pump trials, and HF duration allow detection of patients with the potential to remain stable for >5 post-weaning years.

Heart transplantation in children after mechanical circulatory support with pulsatile pneumatic assist device

BACKGROUND Mechanical support with a pulsatile pneumatic ventricular assist device (VAD) is a complex rescue procedure performed in children with untreatable cardiogenic shock. Its impact on early and long-term survival after subsequent heart transplantation (HTx) remains to be determined. METHODS We reviewed retrospectively the course of 95 children (median age, 8 years; range, 8 days-17 years; body weight, 24 kg; range, 3-110 kg) who underwent HTx. Group A, the elective-HTx group, consists of 33 children who were treated as outpatients before transplantation. Group B, the emergency-HTx group, has 44 children who were critically ill and hospitalized before transplantation but without ventricular assist devices, whereas Group C, the VAD-HTx group, consists of 18 children resuscitated and supported with pulsatile pneumatic VADs for a median time of 20 days. RESULTS Overall actuarial survival after cardiac transplantation was 86% at 1 month, 82% at 1 year, and 78% at 5 years, without significant differences among the 3 sub-groups. Group A had the best long-term survival rate, 88% at 1 month, 88% at 1 year, and 80% at 5 years. Group B had a survival rate of 88% at 1 month, 82% at 1 year, and 79% at 5 years. Group C had a survival rate of 72% at 1 month, 72% at 1 year, and 72% at 5 years. We found no differences in neurologic outcome, acute cardiac rejection, or transplant failure. The survival rate was significantly better in the children with cardiomyopathy compared with those with congenital heart defects (p = 0.014). CONCLUSIONS Bridging to HTx with a pulsatile pneumatic VAD is a safe procedure in pediatric patients. After HTx, overall survival of these children is similar to that of patients who were bridged with inotropes or who were awaiting heart transplantation electively.

Experience with over 1000 Implanted Ventricular Assist Devices

Abstract  Purpose: The use of ventricular assist devices (VADs) in patients with chronic end‐stage or acute heart failure has led to improved survival. We present our experience since 1987. Subjects and Methods: Between July 1987 and December 2006, 1026 VADs were implanted in 970 patients. Most of them were men (81.9%). The indications were: cardiomyopathy (n = 708), postcardiotomy heart failure (n = 173), acute myocardial infarction (n = 36), acute graft failure (n = 45), a VAD problem (n = 6), and others (n = 2). Mean age was 46.1 (range 3 days to 78) years. In 50.5% of the patients the VAD implanted was left ventricular, in 47.9% biventricular, and in 1.5% right ventricular. There were 14 different types of VAD. A total artificial heart was implanted in 14 patients. Results: Survival analysis showed higher early mortality (p < 0.05) in the postcardiotomy group (50.9%) than in patients with preoperative profound cardiogenic shock (31.1%) and patients with preoperative end‐stage heart failure without severe shock (28.9%). A total of 270 patients were successfully bridged to heart transplantation (HTx). There were no significant differences in long‐term survival after HTx among patients with and without previous VAD. In 76 patients the device could be explanted after myocardial recovery. In 72 patients the aim of implantation was permanent support. During the study period 114 patients were discharged home. Currently, 54 patients are on a device. Conclusions: VAD implantation may lead to recovery from secondary organ failure. Patients should be considered for VAD implantation before profound, possibly irreversible, cardiogenic shock occurs. In patients with postcardiotomy heart failure, a more efficient algorithm should be developed to improve survival. With increased experience, more VAD patients can participate in out‐patient programs.

Homograft aortic root replacement in native or prosthetic active infective endocarditis: Twenty-year single-center experience

OBJECTIVE We compared early and long-term results of cryopreserved homograft aortic root replacement in native valve endocarditis or prosthetic valve endocarditis associated with periannular abscess. METHODS Between May 1986 and December 2007, 1163 patients with endocarditis were operated upon. Of these, 221 patients (n = 185 men, median age 55 years) had homograft aortic root replacement due to 99 cases of native valve endocarditis (45%) and 122 of prosthetic valve endocarditis (55%). Perinannular abscess developed in 189 patients (86%), and aortoventricular dehiscence in 120 (63.5%) of them. Perioperative characteristics, probability of survival, freedom from recurrence, and reoperation were analyzed. Follow-up (mean 5.2 +/- 0.4 years, maximum 18.4 years) was completed in 96.8% with a total of 1127 patient-years. RESULTS Overall native valve endocarditis survival at 30 days and 1, 5, and 10 years was 83.8% +/- 3.7%, 76.6% +/- 4.3%, 66.5% +/- 4.9%, and 47.3% +/- 5.6%, respectively, significantly better than for patients with prosthetic valve endocarditis, who had a greater tendency toward abscess formation (P = .029). Thirty-one patients (14.0%) required reoperation either for structural valve deterioration (n = 19, 8.6%), with a greater tendency in patients aged <40 years, or for recurrent endocarditis of the homograft (n = 12, 5.4%). One-year reoperation mortality rate was 16.1% (n = 5). CONCLUSIONS Homograft aortic root replacement in active infective endocarditis with periannular abscess formation shows satisfactory early and long-term results with significantly better survival in native valve endocarditis than prosthetic valve endocarditis. It is associated with a low recurrence rate, although the risk of structural valve deterioration increases over time, especially in young patients, and reoperation remains a challenge. In our institution, the homograft remains the preferred valve substitute in active infective endocarditis with periannular abscess formation.

Using aortic allograft material to treat mycotic aneurysms of the thoracic aorta

BACKGROUND Although mycotic aneurysms are rare in this age of antibiotics, they nevertheless represent life-threatening lesions of the aortic wall because of their high incidence of rupture and significantly high rate of recurrence. METHODS Between March 1988 and August 1994, cryopreserved allograft material was used to treat 8 patients (mean age, 62.5 years; range, 47 to 80 years) with mycotic aneurysms of the thoracic aorta at our institution. Two patients had emergency operations; the other operations in 6 patients were elective. The aneurysms were located at the previous cannulation site of the aorta (n = 1) or at the donor/recipient aortic anastomosis (n = 1) in the patients who had heart transplantation, in the ascending aorta in 3 patients with aortic valve endocarditis, in the aortic arch in 2, and in the descending aorta in 1. The operative technique consisted of excision of the mycotic aneurysm followed by allograft patch reconstruction in 5 patients, an allograft composite graft replacement of the ascending aorta in 2 patients with endocarditis, and combined aortic allograft root replacement and allograft patch reconstruction of the ascending aorta in 1 patient. RESULTS The underlying infections of the aorta were treated successfully in 6 patients. One heart transplant recipient had reoperation because of recurrent mycotic aneurysm after allograft patch reconstruction at the donor/recipient anastomosis. There was one early death involving a patient with Salmonella sp sepsis. CONCLUSIONS The use of aortic allograft material for repairing mycotic aortic aneurysms is a promising and effective operative concept for managing thoracic aortic infections.

Accelerated degeneration of allografts in the first two years of life

Between January 1988 and May 1994, 53 of 159 patients have received cryopreserved aortic and pulmonary allografts for reconstruction of the pulmonary circuit in the first 2 years of life with body weight ranging from 2.2 to 18 kg (mean, 8.2 +/- 3.4 kg). The implanted allografts ranged in internal diameter from 9 to 23 mm (mean, 16.3 +/- 3.5 mm). Of the 38 survivors who regularly had postoperative echocardiographic examinations 15 (39.5%) underwent cardiac catheterization 1 to 31 months after operation. Allograft dysfunction (gradient > or = 50 mm Hg with or without pulmonary insufficiency) was confirmed in 9 patients leading to reoperation in 5 and valvulo-angioplasty in 4. At 48 months actuarial survival was 64%. In the aortic and pulmonary allografts freedom from wall calcification at 20 months was 19% and 100%, respectively. Freedom from valve dysfunction in patients with aortic and pulmonary allografts was 53% and 88%, respectively; it was 49% in allografts with an internal diameter of 17 mm or smaller. Freedom from reoperation in all patients was 78%. In conclusion, young age, antigenicity (ABO compatibility), and type of allograft seemed to be independent risk factors for early allograft conduit degeneration and late valve dysfunction. Pulmonary allografts seemed to be more resistant to early wall calcification and valve dysfunction than aortic allografts.

Decreased plasma concentration of brain natriuretic peptide as a potential indicator of cardiac recovery in patients supported by mechanical circulatory assist systems

OBJECTIVES We sought to investigate the relationship between the plasma concentration of brain natriuretic peptide (BNP), echocardiographic findings and the clinical outcome of patients supported with ventricular assist devices (VADs) to determine the role of BNP as a predictor for cardiac recovery. BACKGROUND Ventricular unloading in patients with end-stage heart failure supported by VADs may lead to myocardial recovery. The BNP is produced in the myocardium in response to chronic volume overload, but the effects on it of ventricular unloading by VADs are largely unknown. METHODS Twenty-one patients diagnosed with nonischemic cardiomyopathy and supported by VADs were evaluated for echocardiographic data and blood chemistry including BNP. They were divided into patients who died while on mechanical support (group I; n = 9), patients who were transplanted (group II; n = 8) and patients who were successfully weaned off the system and did not require transplantation (group III; n = 4). RESULTS Brain natriuretic peptide plasma concentrations decreased significantly after initiation of mechanical circulatory support (p = 0.017). Furthermore, the changes in BNP plasma concentrations showed a faster decrease to normal levels within the first week after implantation of the VAD in patients who were weaned off the system (group III) compared to patients in group I and group II. CONCLUSIONS This study shows that ventricular unloading with VADs decreases BNP plasma concentrations in patients who suffer from end-stage heart failure. Furthermore, we hypothesize that an early decrease of BNP plasma concentration may be indicative of recovery of ventricular function during mechanical circulatory support.