Philip Y.K. Pang

A survivor of late prosthesis migration and rotation following percutaneous transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) has emerged as a viable alternative endovascular technique in selected patients with severe aortic stenosis, who are either inoperable or at high risk for surgical aortic valve replacement. We report a case of delayed displacement and rotation of an aortic bioprosthesis, 43 days after successful TAVI via the transfemoral approach, with the patient surviving the subsequent open heart surgery required for device retrieval.

Surgical management of infective endocarditis: an analysis of early and late outcomes

OBJECTIVES To review our experience of surgical management of infective endocarditis (IE) over a 13-year period and analyse the outcomes and associated prognostic factors. METHODS A retrospective review was conducted for 191 consecutive patients who underwent surgery for native and prosthetic valve endocarditis (PVE) between January 2000 and December 2012. Surgical outcomes were reviewed to include survival and postoperative complications. Follow-up was complete for 172 of 179 patients (96.1%) surviving to hospital discharge, with a mean follow-up of 6.6 ± 3.7 years. RESULTS Mean age was 47.4 ± 14.9 years with 113 (63.9%) males. Native valve endocarditis was present in 177 patients (92.7%). Sixty-three patients (33.0%) presented with embolic complications. The brain was the most common site of embolism, involving 25 patients (13.1%). Streptococcus viridans was the most common infective organism, isolated in 68 patients (35.7%), followed by Staphylococcus aureus in 30 patients (15.7%). Eighty-seven patients (45.5%) had active endocarditis at the time of surgery. The mitral valve was infected in 136 patients (71.2%), the aortic valve in 66 (34.6%), the tricuspid valve in 29 (15.2%) and multiple valves in 38 (19.9%). Nineteen patients (9.9%) were intravenous drug users (IVDU). Twelve IVDUs (63.2%) suffered from tricuspid valve IE, compared with 7 of 162 patients (4.3%) in the non-IVDU population (P < 0.001). The most common indication for early surgery was intractable cardiac failure. Twelve patients (6.3%) died during the hospital stay for surgical treatment of IE. Logistic multivariate analysis identified preoperative creatinine clearance and stroke as independent predictors of in-hospital mortality. Overall 10-year survival and freedom from valve-related reoperation were 74.8 and 90.3%, respectively. Age, PVE, S. aureus endocarditis and postoperative left ventricular ejection fraction (LVEF) ≤45% were factors influencing long-term survival. CONCLUSIONS Surgical management of endocarditis continues to be challenging and is associated with significant morbidity and mortality. This report of 191 patients who underwent valve surgery for IE shows that in-hospital mortality is influenced by preoperative renal function and stroke at the time of presentation. The optimal timing for surgery in patients with stroke remains controversial. Long-term survival was negatively influenced by increasing age, moderate to severely impaired LVEF, prosthetic valve IE and S. aureus infection.

Outcome and survival analysis of intestinal ischaemia following cardiac surgery

OBJECTIVES Intestinal ischaemia is an uncommon (<1%) but serious complication of cardiac surgery with a mortality rate exceeding 50%. Diagnosis of this potentially lethal condition can be difficult and requires a high index of suspicion. The purpose of this study was to analyse the outcomes and prognostic factors in patients who develop intestinal ischaemia following cardiac surgery. METHODS In a retrospective review from August 1999 to December 2010, we identified 31 out of 9925 (0.31%) consecutive patients who developed acute intestinal ischaemia following cardiac surgery at our tertiary centre. RESULTS The overall mortality was 71.0%. The operative mortality was 65.4% in patients who underwent a laparotomy. Survivors of this complication had surgical intervention earlier (7.4 ± 4.9 h) compared with the non-survivors (13.9 ± 11.1 h). A total of 35 perioperative variables were analysed. A univariate analysis identified 12 variables associated with an increased risk of mortality. Logistic multivariate analysis identified the preoperative logistic EuroSCORE and the base excess at the point of diagnosis of intestinal ischaemia as significant predictors of mortality. These factors may aid prognostication in this group of patients. CONCLUSIONS Despite the high mortality rates associated with intestinal ischaemia following cardiac surgery, early diagnosis and surgical intervention remain the only effective means to reduce mortality.

Rupture of GORE-TEX neochordae 10 years after mitral valve repair

The current non-resectional paradigm in mitral valve (MV) repair emphasizes the use of polytetrafluoroethylene (PTFE) for artificial chordal replacement. While excellent long-term durability of repair using PTFE neochordae has been established, there have been rare reports of neochordal rupture at various times after surgery. We report a case of artificial chordal rupture 10 years after anterior mitral leaflet repair, necessitating reoperation. This complication may have been precipitated by maldistributed intracardiac tensile forces as a consequence of a malpositioned annuloplasty band.

Chordal Reconstruction versus Leaflet Resection for Repair of Degenerative Posterior Mitral Leaflet Prolapse

OBJECTIVE To review our experience of mitral valve repair for degenerative posterior mitral leaflet prolapse, comparing the outcomes of chordal reconstruction and leaflet resection. METHODS From 2000 to 2014, 205 patients underwent successful repair for degenerative posterior mitral leaflet prolapse. One hundred and four (51.5%) underwent leaflet resection (group R) and 98 (48.5%) underwent chordal reconstruction (group C). Follow-up was 96.5% complete with a mean follow-up of 6.1 ± 4.0 years. RESULTS Mean age was 57.0 ± 11.0 years. Males accounted for 73.8%. Ring annuloplasty was performed in 195 (96.5%). There were no operative mortalities within 30 days. Overall survival was 97.8% ± 1.3% at 7 years. Outcomes at 6 years: freedom from severe mitral regurgitation (group R 97.1% ± 2.0%, group C 100%, P = 0.288), freedom from moderate or severe mitral regurgitation (group R 97.1% ± 2.0%, group C 94.4% ± 5.4%, P = 0.541). Group C patients received larger annuloplasty rings and had significantly lower postoperative transmitral gradients. CONCLUSIONS Leaflet resection and chordal reconstruction are effective techniques for repair of degenerative posterior mitral leaflet prolapse. Both techniques result in a low incidence of recurrent mitral regurgitation. Chordal reconstruction accommodates larger annuloplasty rings and is associated with lower transmitral gradients.

Comparable perioperative outcomes and mid-term survival in prosthetic valve endocarditis and native valve endocarditis

OBJECTIVES Cardiac surgery for prosthetic valve endocarditis (PVE) represents one of the highest risk surgeries with in-hospital mortality of 20%. Given the complex nature of the operation, the operative outcome is likely strongly susceptible to the surgeons experience and centre case volume, as measurements often are not apparent in large observational studies. We sought to evaluate operative outcomes and mid-term survival of patients with PVE compared with those of native valve endocarditis (NVE) at a tertiary care hospital. METHODS We conducted a single-institutional retrospective review of 188 consecutive patients (146 NVE and 42 PVE) undergoing cardiac surgery for endocarditis between 2011 and 2016 at a tertiary care hospital in the USA. A logistic regression model was fit to evaluate patient characteristics and perioperative outcomes in PVE and NVE: operative mortality and composite events (death, stroke, prolonged intubation, renal failure and sepsis). The Kaplan-Meier analysis was used to estimate the mid-term survival. The Cox proportional hazard model was fit to assess the adjusted risk associated with mid-term survival. RESULTS Operative mortality was 4.1% for NVE and 0% for PVE (P = 0.34). Composite events occurred in 30.6% and 38.1% of NVE and PVE, respectively (P = 0.45). Multivariable logistic regression for composite events showed that PVE was not associated with increased risk of adverse events [odds ratio 1.4, 95% confidence interval (CI) 0.6-3.4; P = 0.49]. The Kaplan-Meier analysis demonstrated no statistically significant difference in survival (P = 0.99). Finally, the Cox proportional hazard analysis for mid-term mortality demonstrated that PVE was not associated with increased risk for hazard of death: hazard ratio 0.4, 95% CI 0.2-1.1; P = 0.085. CONCLUSIONS Surgery for PVE can yield a low mortality rate with mid-term survival comparable with those of NVE. The diagnosis of PVE alone should not deter surgeons from operating on this complex patient population, provided that surgical expertise and experienced multidisciplinary team equipped to handle complex clinical scenarios are available.

Intraoperative Bioprosthetic Valve Dysfunction Causing Severe Mitral Regurgitation

Structural degeneration of bioprosthetic valves usually occurs gradually over time. Failure of a bioprosthetic valve immediately after implantation is extremely rare. Possible causes include obstruction of valve leaflets from preserved subvalvular tissue during chordal-sparing mitral valve replacement (MVR) or strut entrapment by suture loops. We report 2 cases of acute bioprosthetic mitral valve (MV) dysfunction involving newly implanted Perimount Theon (Edwards Lifesciences, Irvine, CA) bioprostheses, causing severe transvalvular mitral regurgitation (MR). Rapid diagnosis was achieved with the use of intraoperative transesophageal echocardiography (TEE). Operative assessment and examination of the explanted valves could not determine a definite cause of failure in either case.

Successful anticoagulation therapy for a giant left atrial thrombus following mitral valve repair

A 72-year-old male with atrial fibrillation (AF) underwent mitral valve (MV) repair and concomitant procedures. He was discharged with therapeutic Warfarin dosing but was readmitted 3 weeks later with a right caudate nucleus infarct and subtherapeutic anticoagulation. Echocardiography showed a giant left atrial (LA) thrombus. Low-molecular-weight heparin was promptly initiated. Unfortunately, the patient suffered an intracranial hemorrhage (ICH) 2 days later. He declined surgical thrombectomy and was managed conservatively, remaining stable without neurological deficits. Serial brain imaging showed interval stability, allowing Warfarin to be resumed. Follow-up echocardiography demonstrated partial and complete resolution of the thrombus at 1 and 3 months, respectively.

Therapeutic Hypothermia May Improve Neurological Outcomes in Extracorporeal Life Support for Adult Cardiac Arrest

BACKGROUND Limited data exists on patients receiving therapeutic hypothermia during extracorporeal life support (ECLS). We investigated outcomes and prognostic factors in these patients. METHODS A retrospective review was conducted for 225 consecutive adult patients treated with ECLS between July 2003 and January 2016. Extracorporeal life support was initiated for refractory cardiac arrest (>10 mins) in 79 patients (35.1%). Patient demographics, ECLS-related complications, in-hospital mortality and neurological outcomes were analysed. RESULTS The mean age was 49.9±12.4 years. Sixty-two patients (78.5%) were male. The mean duration of CPR and ECLS were respectively, 32.0±23.3 mins and 5.4±4.0 days. Therapeutic hypothermia (34oC) was maintained for 24hours in 14 patients (17.7%). Thirty-five patients (44.3%) were weaned off ECLS. Twenty-one patients (26.6%) survived to hospital discharge with 16 (20.3%) recovering good neurological function. Compared to ECLS at normothermia, neurologically favourable survival was higher in the hypothermia group (42.9% vs 15.4%, p=0.020). Multivariable analysis identified a non-shockable rhythm [odds ratio (OR) 5.1, confidence interval (CI) 1.5-16.8], ischaemic hepatitis (OR 6.2, CI 1.1-33.6) and hypoxic ischaemic encephalopathy (OR 5.1, CI 1.5-17.1) as predictors of in-hospital mortality. Therapeutic hypothermia (OR 4.9, CI 1.2-20.4) and acute renal failure (OR 0.19, CI 0.05-0.70) were predictors of neurologically favourable survival. CONCLUSIONS In this report of patients treated with ECLS, in-hospital survival and survival with good neurological performance were 26.6% and 20.3% respectively. A non-shockable rhythm, ischaemic hepatitis and hypoxic ischaemic encephalopathy were predictors of in-hospital mortality. Therapeutic hypothermia during ECLS was associated with improved neurological outcomes.

Surgical management of very late paravalvular leaks after mitral valve replacement: a single institutional experience.

Most mitral paravalvular leaks (PVLs) occur during the first year after mitral valve replacement (MVR). This report describes the surgical management of 6 patients who developed very late mitral PVLs. The median interval between MVR and initial diagnosis of PVL was 16.5 years. All patients presented with congestive cardiac failure and haemolytic anaemia. The median EuroSCORE II was 9.5%. Two patients (33%) had failed attempts at transcatheter closure. Five patients underwent suture repair of the PVL. One patient underwent MVR after removal of the previous prosthesis. No in-hospital mortalities occurred. At latest follow-up (median 3.3 years), 5 patients (83%) were asymptomatic with no residual PVL. Haemolytic anaemia persisted in 1 patient with a mild residual PVL. PVL occurring decades after MVR is a rare but serious complication. Reoperative surgery can be performed in these high-risk patients with satisfactory early and midterm outcomes.