Mild intracerebral bleeding does not adversely affect survival and neurological outcome of surgical therapy for left-sided infective endocarditis

Background: Intracerebral bleeding (IB) is a serious condition that requires increased attention and has implications for treatment options. For patients with infective endocarditis (IE), current guidelines recommend postponing surgery if IB is present. IB can be classified into four relevant groups (following European Cooperative Acute Stroke Study and Heidelberger Bleeding classification): hemorrhagic transformation (HT) 1 and 2, and parenchymal hemorrhage (PH) 1 and 2. PH2 is the only IB with neurological deterioration. These classifications were originally introduced for stroke patients following thrombolysis but without IE. The hypothesis tested in our study is that IB may influence IE treatment and thus outcome.

Method: Patients were retrospectively identifyied who were operated for left-sided IE, neuroradiologists re-evaluated and classified preoperative cerebral imaging for any IB. Outcome was quantified using the modified Rankin score (mRS), and mRS were extracted from the patients’ hospital chart at admission and by follow-up telephone call (FU), also including mortality. To ensure that the influence of IB was comparable, patients with IB (IB+) were propensity matched (EuroScore 2, Charlson Comorbidity Index, C-reactive protein; nearest neighbor match) to patients without IB (IB-) who also received surgical IE therapy. All IB+ patients underwent a careful risk-benefit analysis before therapy.

Results: Of 286 consecutive patients (January 2015 - November 2022) operated for left-sided IE, 36 had IB (65±13 years, 26% female): 11 with HT1, 9 with HT2, 8 with PH1, and 8 with PH2. These patients were matched with 36 operated IB- patients. Survival analysis showed no overall effect of IB+ vs. IB- (p = 0.112, 95% CI of hazard ratio was 0.246-1.243 vs. 0.709-3.572). Although there was no effect of IB on survival in the mild IB subgroup (HT1/2, Figure A), there was a difference in patients with  severe IB (PH1/2) with less survival in IB+ (Figure B). Neurological outcome (ΔmRS) showed an effect of IB grade in the two-way ANOVA analysis (p = 0.029). Intergroup comparison showed a significantly better outcome for IB- (vs. IB+) in the PH2 subgroup (p = 0.034), but not in other subgroups. For all groups, the mean ΔmRS for IB+ was 1.1±1.6 vs. 0.70±1.4 for IB- (p = 0.256). The mean FU time was 2.6±2.1 years.

Conclusion: In patients operated for left-sided IE, mild IB did not affect survival or neurological outcome. In the more severe forms of IB, i.e. PH1 and PH2, survival was less favorable compared to matched controls. Furthermore, we observed a difference in neurological outcome in patients with severe IB. Thus, surgical therapy of left-sided IE should be avoided in patients with severe IB, whereas we can add evidence to the safety of surgical therapy in mild IB. Therefore, we recommend regular assessment of the degree of IB in such patients.