It has been known that hypertension is one of the most important risk factors for aortic dissection . However, the predictive value of hypertension in patients of TA-AAD underwent cardiac surgeries remained understudied. Therefore, we examined the association between preexisting hypertension and patients’ short- and long-term mortality rates in our hospital. In this study, we demonstrated that complicating with hypertension did not increase patients’ mortality rate within 30 days after surgery. However, the long-term survival rate of hypertensive patients was significantly lower than that of normotensive patients. In addition, hypertension was identified as an independent predictor for increased long-term mortality rate.
Compared to previous studies that trying to decipher the influence of blood pressure on patients with TA-AAD [8, 9], one of the strengths of this study was that we applied PSM methods on the cohort before further analysis. As a result, confounders that might bias the results were excluded between two groups. The patient cohort analyzed in our study comprised of consecutively enrolled patients who underwent surgical repair of TA-AAD. In our cohort, 492 patients (69.1%) were complicated with hypertension, a percentage that in consistent with previous studies [5, 10–13]. Our clinical profile depictions suggested that hypertensive patients were older and heavier than normotensive patients, similar to previous reports [8, 9, 14]. Unsurprisingly, hypertensive patients were associated with significantly elevated preoperative sCr, which was also in consistent with other reports [9, 15]. Most studies started their survival analysis on hospital day 1 thereby included in-hospital deaths. It is important to notice that we only count deaths that happened after hospital discharge in this study which might gave us an under-estimated mortality rate when comparing to other studies.
Another important finding in our study was that hypertensive patients received less aortic valve management. However, normotensive patients tend to be younger in our study and we could not rule out the influence of age on disease manifestations and procedure selections. As a matter of fact, reports from IRAD investigators suggested that younger patients more often underwent root surgeries .
In the present study, we found that hypertension was not associated with increasing peri-operative mortality rate. Several reports analyzing the influence of preoperative factors on the survival of patients with TA-AAD found a similar result that hypertension was not an independent predictor of higher operative mortality [8, 17–19]. One reason might be that the patients’ BP was closely monitored and proper antihypertensive medications were prescribed during hospitalization period. Another reason might be that the area of greatest aortic shear stress was surgically repaired and the risk of developing a new separation of the aortic vessel layers was minimized.
Our findings suggested that after aortic repair surgeries, hypertension was associated with patient’s long-term survival. Similar to other studies, main reasons for late death in our cohort were cardiac failure and aortic rupture . Strict BP control after discharge is pivotal in the management of patients experienced aortic dissection. Unfortunately, it is difficult to achieve in some patients. From a nationwide database of 276,197 subjects (aged 40–75 years), there were 123,063 hypertensive patients, and only 77,379 (63%) received proper anti-hypertensive drugs. Another research found that only 598 out of 848 (70.5%) hypertensive patients received regular medication in China . Poor medication adherence and BP control contribute to the developing of TA-AAD in vulnerable population. A previous report demonstrated that an increase in BP of 26 mm Hg was equivalent to an increase of the aortic diameter of 1 centimeter . An 25 years follow-up study of 252 patients who underwent repair of TA-AAD suggested that the reoperation probability was markedly decreased with improved systolic BP control . Tsai and associates examined 303 consecutive patients with TA-AAD concluded that patents who died within 3 years of surgery had increased systolic BP compared with those who survived (130 vs 122, P < 0.01) .
Contrary to our conclusions, Merkle and colleagues  demonstrated that hypertensive patients were not associated with worse long-term survival compared to normotensive patients. However, compared to their study, we involved more cases and more sophisticated statistical analysis like PSM and Cox regression analysis to eliminate potential bias in baseline characteristics, which might render us a better strength. And it is important to point out that ethnics might also play an important role. In addition, the observation in a cohort consisted of 232 consecutive patients treated surgically for TA-AAD followed up to 4 years supported our findings . Numerous studies, including us, proved that in order to prevent late adverse events, frequent follow-up and appropriate medication are essential for patients who have undergone aortic repair for TA-AAD.
In the present study, our data showed a clear trend, though did not reach statistical significance, that age predicted a worse prognosis in long term while TAR procedure was associated with a better long-term mortality, suggested by Cox regression analysis (P = 0.061, P = 0.073; Respectively). Previous studies demonstrated that age was an independent predictor of late mortality for TA-AAD patients [19, 21]. Improvement of long-term prognosis after surgical repair of TA-AAD mainly depends on the reduction of complications related to the distal false lumen. It has been known that TAR procedure could diminished the tear and accelerated thrombosis rates of the residual false lumen and led to excellent late results . Heo et al.  reported that an entry resection was important to prevent aortic events during the late phase. Thus, in order to reduce severe aortic events in the long term, it is advisable to replace the aortic arch during the surgery.