Takotsubo cardiomyopathy and summer: a dangerous liaison?

Risk stratification algorithm for clinical outcomes in anemic patients undergoing percutaneous coronary intervention

BACKGROUND

To explore the crosstalk between baseline or visit hemoglobin and major adverse cardiovascular and cerebral events (MACCE) in percutaneous coronary intervention (PCI) patients and to construct risk stratification models to predict MACCE amongst these patients.

MATERIALS AND METHODS

We conducted a retrospective cohort in patients undergoing PCI procedures at Beijing Friendship Hospital between January 2013 and December 2020. Multivariate Cox proportional hazards models were employed for data analyses. The composite MACCE was the primary endpoint and we used machine learning algorithms to evaluate risk factors associated with MACCE. Model performance was measured using Brier scores and receiver-operating characteristic curves. The association between risk factors and MACCE probability was examined using partial dependency plots.

RESULTS

8,298 PCI-treated patients were enrolled in the study. 1,919 of these patients had anemia. During a four-year median follow-up period, 1,636 patients (19.71%) had MACCE. The visit hemoglobin and hemoglobin change was associated with higher risk of MACCE respectively (visit hemoglobin: hazard ratio [HR]: 0.98; 95% confidence interval [CI]: 0.98-0.99; p < 0.001; hemoglobin change: HR: 0.99; 95%CI: 0.98-0.99; p < 0.001). Gradient Boosting (GB) was the BPM, with a mean C-statistic value of 0.78 (95% CI: 0.76-0.80) for predicting MACCE (Brier score: 0.26). The best indicator for MACCE was a low estimated glomerular filtration rate [eGFR] (71 mL/min/1.73m2) at admission, followed by a high serum HbA1c (6.6%) level. A simple risk tree successfully classified patients (17-40.5%) with increased risks of MACCE. The high- vs. low-risk HR for MACCE was 2.04 (95% CI: 1.48-2.82).

CONCLUSIONS

Visit hemoglobin and long-term hemoglobin changes were more predictive of MACCE risk than baseline hemoglobin levels. Our findings indicated that increasing hemoglobin levels might improve the long-term prognosis of anemia patients. We established a new risk stratification model for MACCE, which may more efficiently prioritize targeted screening for at-risk anemic patients undergoing PCI.

Epidemiology and clinical profile of Takotsubo cardiomyopathy

First described in Japan over 2 decades ago, takotsubo cardiomyopathy (TTC) has emerged as a unique cardiomyopathy with world-wide recognition, mimicking acute coronary syndrome. In early TTC experience, typical patients were older women, with a triggering emotional event, ST-segment elevation, and apical ballooning left ventricular (LV) contraction pattern. However, TTC is now more heterogeneous, occurring in males and younger individuals, without ST-segment elevation, as a spontaneous event in the absence of a trigger, and with diverse LV contraction patterns. Furthermore, TTC is more common than initially thought, now constituting 10% of women with suspected acute coronary syndrome. TTC is also associated with a broader range of psychological or physical triggers, including presentation during outpatient medical evaluations or hospitalization for acute illness. Although TTC has been considered a benign condition, it now carries a small but important risk for adverse outcomes, including cardiac arrest in 5%. Hemodynamic instability requiring intervention with vasopressor drugs or intra-aortic balloon pump is necessary in 15% and in-hospital mortality is approximately 5%, largely because of refractory cardiogenic shock or irreversible major comorbid conditions. Although complete cardiac recovery usually occurs rapidly, post-hospital survival may be less than the general population of similar age, largely because of concomitant illnesses. TTC may reoccur in up to 10% of patients, but β-blocking drugs are not absolutely preventive for initial or subsequent events.