Comparison of allografts and prosthetic valves when used for emergency aortic valve replacement for active infective endocarditis

Long-Term Follow-Up after Mycobacterium Chimaera Infection Following Cardiac Surgery: Single-Center Experience

BACKGROUND

Disseminated Mycobacterium chimaera (M. chimaera) infection following cardiac surgery has been associated with a high mortality. The long-term impact of surgery and the appropriate surgical approach are still matters of debate.

METHODS

From 2015 to 2019, seven patients with M. chimaera infection following cardiac surgery were isolated.

RESULTS

The median incubation time was 30 months (IQR 18-38). Echocardiography was unremarkable in three patients (43%). We decided to redo cardiac surgery in all patients and explanted all previously implanted prosthetic material. All explant cultures yielded M. chimaera. One patient (14%) died in-hospital seven months after the redo surgery. After a median follow-up of 59.6 months (IQR 39.1-69.6), we observed three infection relapses among the survivors (43%), presumably due to concomitant extracardiac infection and recurrent cardiac implant infection.

CONCLUSIONS

M. chimaera infection following cardiac surgery is associated with a delayed and unspecific clinical presentation. Echocardiogaphy has a limited sensitivity for prosthetic valve infection with M. chimaera, and negative findings should not preclude the surgical decision. The extraction of all previously implanted material is crucial to achieving the source control, as the re-implantation of prosthetic material as well as uncontrolled extracardiac infection at the time of the redo cardiac surgery appear to be key factors for persisting/relapsing infection.

Homograft Versus Valves and Valved Conduits for Extensive Aortic Valve Endocarditis with Aortic Root Involvement/Destruction: A Systematic Review and Meta-Analysis

Aortic valve infective endocarditis is a life-threatening condition. Patients frequently present profoundly unwell and extensive surgery may be required to correct the underlying anatomical deficits and control sepsis. Periannular involvement occurs in more than 10% of patients with aortic valve endocarditis. Complex aortic valve endocarditis has a mortality rate of 10 to 40%. Longstanding surgical dogma suggests homografts represent the optimal replacement option in complex aortic valve endocarditis; however, there is a paucity of evidence and lack of consensus on the optimal replacement choice. A systematic review and meta-analysis was performed utilizing EMBASE, PubMed, and the Cochrane databases to review articles describing homografts versus aortic valve replacement and/or valved conduit graft implantation for complex aortic valve endocarditis. The outcomes of interest were mortality, reinfection, and reoperation. Eleven studies were included in this meta-analysis, contributing 810 episodes of complex aortic valve endocarditis. All included reports were cohort studies. There was no statistically significant difference in overall mortality (risk ratio [RR] 0.99; 95% confidence interval [CI], 0.61–1.59; p  = 0.95), reinfection (RR 0.89; 95% CI, 0.45–1.78; p  = 0.74), or reoperation (RR 0.91; 95% CI, 0.38–2.14; p  = 0.87) between the homograft and valve replacement/valved conduit graft groups. Overall, there was no difference in mortality, reinfection, or reoperation rates between homografts and other valve or valved conduits in management of complex aortic endocarditis. However, there is a paucity of high-quality evidence in the area, and comparison of valve types warrants further investigation.

Drug Use and Postoperative Mortality Following Valve Surgery for Infective Endocarditis: A Systematic Review and Meta-analysis

BACKGROUND

Infective endocarditis (IE) often requires surgical intervention. An increasingly common cause of IE is injection drug use (IDU-IE). There is conflicting evidence on whether postoperative mortality differs between people with IDU-IE and people with IE from etiologies other than injection drug use (non-IDU-IE). In this manuscript, we compare short-term postoperative mortality in IDU-IE vs non-IDU-IE through systematic review and meta-analysis.

METHODS

The review was conducted according to the Cochrane Handbook for Systematic Reviews of Interventions and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Publication databases were queried for key terms included in articles up to September 2017. Randomized controlled trials, prospective cohorts, or retrospective cohorts that reported on 30-day mortality or in-hospital/operative mortality following valve surgery and that compared outcomes between IDU-IE and non-IDU-IE were included.

RESULTS

Thirteen studies with 1593 patients (n = 341 [21.4%] IDU-IE) were included in the meta-analysis. IDU-IE patients more frequently had tricuspid valve infection, Staphylococcus infection, and heart failure before surgery. Meta-analysis revealed no statistically significant difference in 30-day postsurgical mortality or in-hospital mortality between the 2 groups.

CONCLUSIONS

Despite differing preoperative clinical characteristics, early postoperative mortality does not differ between IDU-IE and non-IDU-IE patients who undergo valve surgery. Future research on long-term outcomes following valve replacement is needed to identify opportunities for improved healthcare delivery with IDU-IE.

Homograft Versus Conventional Prosthesis for Surgical Management of Aortic Valve Infective Endocarditis: A Systematic Review and Meta-analysis

OBJECTIVE

Surgical management of aortic valve infective endocarditis (IE) with cryopreserved homograft has been associated with lower risk of recurrent IE, but there is equipoise with regard to the optimal prosthesis. This systematic review and meta-analysis were performed to compare outcomes between homograft and conventional prosthesis for aortic valve IE.

METHODS

We searched MEDLINE database to September 2017 for studies comparing homograft versus conventional prosthesis. The main outcomes were all-cause mortality, recurrent IE, and reoperation.

RESULTS

There were 18 included comparative observational studies with 2232 patients (median follow up = 5 [interquartile range: 2-7] years, 30% prosthetic valve endocarditis); four studies were adjusted for baseline differences. There were no differences in perioperative mortality or stroke despite a greater proportion of staphylococcal endocarditis, abscess, and root replacements but less multivalve involvement in the homograft group. Long-term outcomes of all-cause mortality [incidence rate ratio (IRR) = 1.03, 95% confidence interval (CI) = 0.81-1.31, P = 0 .83, for unmatched, and IRR = 0.82, 95% CI = 0.36-1.84, P = 0.63, for matched studies], recurrent endocarditis (IRR = 1.01, 95% CI = 0.53-1.93, P = 0.96, for unmatched, and IRR = 1.04, 95% CI = 0.49-2.19, P = 0.92, for matched studies), and reoperation (IRR = 1.60, 95% CI = 0.80-3.21, P = 0.18, for unmatched, and IRR = 3.17, 95% CI = 0.52-19.44, P = 0.21, for matched studies) were not different comparing homograft versus conventional prosthesis. There was a significantly increased need for reoperation with homograft versus mechanical prosthetic valves, but this comparison was based on limited data.

CONCLUSIONS

Homografts and conventional prostheses offer similar survival and freedom from recurrent endocarditis and reoperation for aortic valve IE. Homografts may be associated with greater risk of reoperation compared with mechanical valves.

Repair versus replacement of the aortic valve in active infective endocarditis

OBJECTIVES

Aortic valve repair has advantages over replacement in stable aortic regurgitation. It is unclear whether this is similar in active endocarditis.

METHODS

From January 2000 to July 2009, 100 patients (age 54.9±15.1 years) underwent surgery for aortic valve endocarditis. Thirty-three patients were treated by valve repair (I) and 67 underwent valve replacement (II: 51 biologic, 10 mechanical valves, 6 Ross operations). In Group I, cusp and root lesions were treated by autologous pericardial patches. A root abscess was present in 32 cases (I: 27%, II 34%; P=0.82). Concomitant procedures (n=49) were mitral repair (I: 10, II: 11; P=0.12) and coronary bypass (I: 4, II: 11; P=0.77). All patients were followed. Cumulative follow-up was 268 patient-years (mean 2.7±3.0 years). In a retrospective analysis, we analysed the outcome.

RESULTS

Hospital mortality was 15% (I: 9%, II: 18%; P=0.37). Survival at 5 years was significantly better after repair (I: 88%, II 65%; P=0.047). Ten patients were reoperated (I: 35%, II: 10%; P=0.021) between 1 month and 5 years postoperatively. Actuarial freedom from aortic regurgitation of grade II or higher was 80% at 5 years (I: 66%, II: 87%; P=0.066). In Group I, this was influenced by aorto-ventricular (AV) morphology (tricuspid 80%, bicuspid 50%; P=0.0045). Freedom from reoperation in reconstructed tricuspid valves (n=20) was 87% at 5 years, which was identical to Group II (P=0.40). At 5 years, freedom from thromboembolic events was 93% (I: 100%, II: 90%; P=0.087) and that from bleeding complications was 100%.

CONCLUSIONS

AV repair for active endocarditis seems to lead to better survival compared with replacement. The use of large patches in combination with bicuspid anatomy results in increased risk of late failure.

Tissue-engineered heart valve prostheses: ‘state of the heart’

In this article, we will review the current state of the art in heart valve tissue engineering. We provide an overview of mechanical and biological replacement options, outlining advantages and limitations of each option. Tissue engineering, as a field, is introduced, and specific aspects of valve tissue engineering are discussed (e.g., biomaterials, cells and bioreactors). Technological hurdles, which need to be overcome for advancement of the field, are also discussed.

Early experience of aortic valve replacement with the Freestyle stentless aortic bioprosthesis in elderly patients

OBJECTIVES

Stentless bioprostheses have been gaining popularity in recent years as hemodynamically superior alternatives to conventional stented bioprostheses.

METHODS

Between July 1996 and November 1998, 13 patients with aortic valve disease, 7 males and 6 females with a mean age (+/- SD) of 68 +/- 5 years, underwent an aortic valve replacement using the Medtronic Freestyle aortic bioprosthesis. The predominant lesions were stenosis in 8 patients and regurgitation in 5, while 2 patients had endocarditis. The operation was performed by a subcoronary technique in 9, root-inclusion technique in 3, and full root technique in 1 patient.

RESULTS

Throughout the follow-up periods (with average follow-up period of 20.6 months), there was no hospital mortality, though there was one late death of unknown cause. The New York Heart Association class improved in all patients. The peak transvalvular gradient decreased from 18.4 +/- 9.8 to 12.6 +/- 9.6 mmHg, and the effective valve orifice area increased from 2.30 +/- 0.96 to 2.59 +/- 1.05 cm2 between the 1-month and the 6-month follow-up examinations. In patients with aortic regurgitation, the left ventricular end-diastolic/end-systolic volume index significantly decreased from 147 +/- 36/62 +/- 19 to 73 +/- 26/33 +/- 14 ml/m2 at 1 month after the operation. The left ventricular mass index also significantly decreased from 189 +/- 26 to 143 +/- 30 g/m2 in patients with aortic regurgitation and from 171 +/- 28 to 144 +/- 30 g/m2 in those with aortic stenosis.

CONCLUSIONS

Although long-term follow-up is required for further evaluation, the early results appeared to indicate that the Freestyle aortic bioprosthesis was suitable for elderly patients requiring aortic valve replacement.