Valve replacement surgery is the second most commonly performed open heart surgery in Jordan, after CABG. However, independent predictors of mortality after valve operations have not been studied as widely as predictors after CABG. This paucity of data might be due to fewer valve operations being performed than CABG procedures; valve operations require more time and/or more centers to accumulate enough cases to draw conclusions. In addition, a wide range of valve procedures are performed, and the risk of mortality may vary with the type of procedure . We have evaluated predictors of mortality and morbidity for patients undergoing CABG [5–7]. Predictors of mortality include age > 65 years, female sex, HF, left ventricular ejection fraction (LVEF) ≤ 35%, prolonged inotropic support, mechanical ventilation > 2 hours, postoperative pneumonia, and postoperative stroke, as well as enlarged left atrial size and mitral regurgitation [5–7]. Previous studies have identified predictors of mortality in different patient populations undergoing valve surgery. In those undergoing mitral valve replacement, postoperative higher creatinine, low cardiac output, small mitral valve size, and new-onset atrial fibrillation were significant independent predictors of morality .
Our study highlights important preoperative, intraoperative, and postoperative predictors that might increase risk of mortality in patients undergoing various types of valve surgery. Consistent with previous studies [3, 4], increased age was found to be a predictor of 30-day mortality in our study population. Older patients have multiple comorbidities with deterioration of organ function. In patients > 80 years old, emergency surgery and CABG were the most important predictors of early mortality after mitral valve surgery (both repair and replacement), with estimated mortality of 18% . Similarly, in patients undergoing AVR, emergency surgery, atrial fibrillation, and older age were the strongest predictors of mortality . Most of our cases were rheumatic in nature (89%). This usually starts at a young age, and over time patients develop progressive deterioration in left ventricular function. Left ventricular dysfunction was shown to be a strong predictor of mortality after valve replacement surgery .
Emergency/salvage surgery was found to be an independent predictor of 30-day mortality, similar to other study results [10, 11, 7]. The pathologies that mandate emergency valve surgery, including acute mitral incompetence following acute myocardial infarction or acute valve incompetence secondary to infective endocarditis, put the patient in a state of acute HF, increasing the risk of death.
Patients who received biological valves were usually older than those who received mechanical valves. However, our model identified both age and biological valves as significant, yet independent, predictors of mortality after adjusting for other variables. In a sub-analysis in which we excluded age from the regression model, the effect of valve type was almost identical to that reported with age in the model, suggesting that 30-day mortality is affected by age independent of valve type and vice-versa.
Beta-blockers are key medications for treating HF, myocardial infarction, and atrial fibrillation and are useful adjuncts for hypertension. Beta-blockers can antagonize the effects of an overactive sympathetic nervous system, which is responsible for development and progression of HF. These medications reduce myocardial oxygen demand and improve LVEF in patients with HF  and control heart rate in patients with mitral stenosis .
Due to their negative inotropic and chronotropic effects, beta-blockers may initially worsen edema, hypotension, bradycardia, and LVEF before improvement is seen, but subsequent improvement often occurs after 6 to 12 months of therapy . The incidence and severity of beta-blockers’ adverse effects are usually dose dependent ..Thus, patients should be clinically monitored and their dose titrated carefully to avoid adverse outcomes. Given the different effects of beta-blockers, increasing the dosage may cause unintended side effects and significant morbidity, particularly in patients with hypotension and bradycardia, without additional benefits .
In our study, most patients were on high doses of beta blockers. Interestingly, use of beta-blockers for less than 1 month before surgery increased the risk of mortality relative to that of non-users, suggesting that short-term use might worsen symptoms and increase mortality risk. To test this hypothesis, we evaluated the correlation between use of beta-blockers for less than 1 month and LVEF as well as presence of orthopnea and found a positive correlation. Current guidelines recommend beta-blocker therapy for patients with mild to moderate compensated HF, with stable New York Heart Association class II/III symptoms and on standard therapy for HF (diuretics and an ace inhibitor) . Intriguingly, beta-blockers were found to increase risk of sudden cardiac death and need for surgery in patients with chronic, severe, non-ischemic MR .
Taylor et al. found postoperative atrial fibrillation (POAF) to be a predictor of mortality after valve replacement surgery , whereas AlWaqfi et al. found no relation . Similarly, we did not find a correlation between POAF and mortality. This might be due to the low prevalence of POAF (12%) in our study.
This is a retrospective study with a limited sample size and some missing data. Data were extracted from a single center, which may not represent short-term mortality in all centers in Jordan.