Langzeitresultate der chirurgischen Behandlung der akuten Aortenklappenendokarditis

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 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.

Early and mid–term results of the Shelhigh stentless bioprosthesis in patients with active infective endocarditis

AIMS

This study investigated the early and mid-term results following valve replacement with the new Shelhigh stentless bioprosthesis made entirely of biological material in patients with active infective endocarditis (AIE).

MATERIAL AND METHODS

Between 02/2000 and 12/2004, 164 patients (n = 122 men, mean age 59, 18-85 years) received implantation of an AIE Shelhigh stentless bioprosthesis in the aortic, mitral, tricuspid or pulmonary position. A total of 119 patients (72.6%) had native AIE and 45 (27.4%) prosthetic AIE. A large proportion of the patients reached the operating room in a condition of cardiac decompensation: 37 (22.6%) patients were intubated, 40 (24.4%) had protracted septic shock and 41 (25.0%) required intensive catecholamine treatment. Surgery was regarded as urgent in 94 patients (57.4%) and was performed as an emergency procedure in 70 (42.6%). The mean follow-up time is 1.5 +/- 0.11 years (range, 5 months to 5.2 years). Echocardiographic follow-up examinations were performed early postoperatively and after 12 months.

RESULTS

In terms of the operative indication, we found a highly significant difference in the survival rate between patients who were operated on urgently vs in an emergency. In patients who died within 30 days, the main cause of death was septic multiorgan failure (67.6%). Only three patients required reoperation due to reinfection of the Shelhigh bioprostheses; this represents a reinfection rate of 1.8% in relation to the whole cohort. The postoperative echocardiographic examinations showed the Shelhigh valves to have very good hemodynamics without relevant pressure gradients.

CONCLUSION

Our experience in the use of Shelhigh bioprostheses in patients with native and prosthetic endocarditis show the early and mid-term results, in particular the low reinfection rate and the good hemodynamics, to be comparable with the results achieved using homografts. Since these prostheses are readily available and their implantation straightforward, they are increasingly being used in patients with endocarditis. These promising results need to verified in the long term.

Native infective endocarditis: Which determinants of outcome remain after surgical treatment?

Surgical therapy of native infective endocarditis is still considered as a particular challenge, due to remaining morbidity and mortality up to 20%. Further risk analysis and characterization of clinical features is of great importance for further improvement of surgical results. The aim of this retrospective study was a risk analysis concerning clinical features of the pre-, intra- and postoperative period. Between 02/1997 and 12/2003, 165 patients (130 male, 35 female, age 55.5 +/- 13.8 years) were referred for surgical therapy of infective endocarditis at our institution. Preoperative, intraoperative and postoperative features were evaluated for their influence on the early postoperative course and the mid-term follow-up. In the majority of patients (pts) the aortic valve was infected (n = 83, 50.3% of pts), followed by mitral valve (n = 33; 20.0%), tricuspid valve (n = 10, 6.0%) and pulmonary valve (n = 2; 1.2%). Double valve affection was recorded in 37 pts (22.4%). Streptococci (n = 66, 40.0%) and staphylococci (n = 66, 40.0%) were the most common pathogens. The overall hospital mortality rate was 10.9% (n = 18), during follow-up (mean follow-up 3.3 +/- 2.5 years) a further 20 pts (12.1%) died.Main predictors for hospital mortality in multivariate analysis were older age (p = 0.01), prolonged ICU stay, prolonged intubation (p = 0.03; p = 0.02) and the continuous postoperative need of alpha-catecholamine medication (p < 0.01). Significant predictors of overall mortality were older age (> 70 years) and diabetes (p = 0.03; p = 0.03). Reinfection occurred in 6.1% of patients (n = 10). Actuarial freedom from recurrent infection was 97% at 1 year and 93.9% at 5 years. Surgical therapy of infective endocarditis is associated with good clinical results in the early and mid-term follow-up. Predictors of outcome particular include preoperative risk constellation or comorbidity (age, diabetes) and variables of the immediate postoperative course.

Regression of medial elastocalcinosis in rat aorta: a new vascular function for carbonic anhydrase

BACKGROUND

We sought to determine whether carbonic anhydrase (CA), which plays an important role in bone resorption, contributes to vascular mineral loss induced by an endothelin receptor antagonist.

METHODS AND RESULTS

Wistar rats were compared with rats receiving warfarin and vitamin K1 (WVK) for 8 weeks alone or in association with the endothelin receptor antagonist darusentan (30 mg/kg per day), the CA inhibitor acetazolamide (100 mg/kg per day), or both for the last 4 weeks. Rats were also treated with WVK for 5 or 6 weeks, and darusentan was added for the last week or last 2 weeks of treatment, respectively. Treatment with WVK produced medial elastocalcinosis in the aorta and carotid arteries. Immunohistochemistry revealed that CA II was already abundant in the adventitia and in calcified areas of aortic sections from WVK-treated rats. Darusentan did not significantly modify its abundance or distribution. In contrast, CA IV immunostaining, which was weak in WVK-treated rats, became apparent after 1 week of darusentan treatment and declined toward basal levels thereafter. These findings were confirmed by a parallel increase in CA IV protein abundance and activity in the aorta. The mineral loss induced by darusentan was blunted by acetazolamide treatment, confirming the functional relevance of the biochemical findings. Moreover, CA IV immunostaining was enhanced much later in the carotids, where darusentan did not cause regression of elastocalcinosis.

CONCLUSIONS

Vascular mineral loss induced by the blockade of endothelin receptors seems dependent on the activation of membrane-bound CA IV, suggesting that mineral loss may proceed via local changes in pH similar to that seen in bone resorption.

Effects of LDL, cholesterol, and their oxidized forms on the precipitation kinetics of calcium phosphates

BACKGROUND

LDL, cholesterol, and their oxidized forms are known cardiovascular risk factors and are often found in atherosclerotic lesions of various stages. Little is known, however, about whether they are directly involved in the formation of calcium phosphate compounds.

METHODS

We used the pH-stat technique to follow the kinetics of calcium phosphate precipitation at pH 7.4, 37 degrees C, and ionic strength 0.150 mol/L, in the presence or absence of LDL, oxidized LDL, cholesterol, cholestane-3beta,5alpha,6beta-triol, and cholesteryl linoleate. The precipitates were characterized by x-ray diffraction, scanning and transmission electronic microscopy coupled with energy-dispersion x-ray analysis, and inductively coupled plasma atomic emission spectroscopy.

RESULTS

Under the experimental conditions, LDL (14.8 and 43.1 mg/L protein) had no significant effect on the precipitation kinetics. Oxidized LDL (14.8 and 43.1 mg/L protein) prolonged the nucleation phase and diminished the amount of total precipitate, and both the extent of oxidation and the concentration of the protein affected the kinetics. Cholesterol microcrystals (71.4 and 143 mg/L) made the nucleation phase shorter (300 min vs 390 min for the control), and the precipitated particles had an organic core and a shell composed of calcium phosphates. L-alpha-Phosphatidylcholine vesicles (143 mg/L), cholesterol (71.4 mg/L)/phospholipid (143 mg/L) mixed vesicles, cholesteryl linoleate (143 mg/L), and cholestane-3beta,5alpha,6beta-triol (71.4 mg/L) prolonged the nucleation phase.

CONCLUSIONS

LDL is not involved directly in the precipitation of calcium phosphates. Oxidized LDL inhibits both nucleation and crystal growth, possibly by attracting calcium ions in the solution and thus reducing supersaturation. Cholesterol microcrystals serve as seeds for the precipitation of hydroxyapatite, whereas L-alpha-phosphatidylcholine, cholesteryl linoleate, and cholestane-3beta,5alpha,6beta-triol exhibit inhibitive effects on the nucleation of calcium phosphates.