Results:
Quantitative variables were expressed as mean, standard deviation. Qualitative variables were expressed as proportions.
Data analysis was done using SPSS version 16.0
According to the age group distribution of the disease (severe PHT) , we can see from the fig 3 ,that the age group affected is mostly from 20 yrs to 50 yrs (90.1 %) .This is a productive age group and needs to be addressed carefully
While considering the sex of the population affected its seen that females are slightly more affected (54.7%) compared to males (45.3%) as evident from the fig 4.
On comparing the tables 1 and 2, we could decipher that most of the patients in the preoperative period were in class III NYHA (67.5 %) and were symptomatically improved to NYHA class II (68.7%). On performing the chi square test it was statistically found to be significant p <0.001
On statistically analyzing the results for the regression in Pulmonary Hypertension following Mitral valve Replacement in our study, we could definitely appreciate that the regression starts from the first month of post surgical period and continues till 3 months post surgical period (p 0.026; p0.095) Table 3 which is quite significant statistically .It’s quite interesting to note that the regression is not appreciable after 3 months as is evident from the fig. 3
The Kaplan Meir curve depicts the drastic regression at 1 month of surgery and gradual regression thereafter in the following months.
As far as the age groups are compared it’s not statistically seen that significant regression occurs following Mitral Valvular Replacement due to severe pulmonary Hypertension .In other words Age doesn’t influence much in the regression of PHT after Mitral valve replacement in patients with severe PHT preoperatively[Table 5 ] .
DISCUSSION :
Normal Pulmonary arterial pressure in a person living at sea level has a mean value of 12–16 mm Hg (1600–2100 Pa). Pulmonary Hypertension is present when mean Pulmonary artery pressure exceeds 25 mm Hg (3300 Pa) at rest or 30 mm Hg (4000Pa) with exercise [9].
PHT can be idiopathic or familial with various underlying causes and classifications. PHT classifications were modified regularly for better understanding of the disease .the latest modification was done in Nice, France 2013. [Table 1] The reduction of PHT following MVR is not well understood and relies on various factors[10,11]. This is a follow up study providing information on the agenda.
In all our 265 patients who underwent MVR, 195 had severe Pulmonary Hypertension females 111/195(56.9%) outnumbered the males in this diagnosis. The immediate reduction of Pulmonary Hypertension happened in only approximately 21 % of the patients and the remaining had persistent PHT which showed a fall progressively following a 1-3 months period suggesting the various factors which might be responsible for the Pulmonary Hypertension.
Yang and colleagues found the long term survival was inversely related to the degree of PHT and had an early (30 day) mortality of 9% in patients with severe PHT, However in our study it was found to be only 5.3% .But it needs further follow up of these patients in the long run. [12].
Cesjnvar et al has reported higher early mortality among his series of 382 patients who underwent MVR for Mitral Valvular disease with Pulmonary Hypertension. But the late mortality was no different among patients with or without Pulmonary Hypertension [13].In our study the mortality was 5.3%, which was less compared to the previous studies. The difference might be because of the earlier decision to operate upon this severe group before irreversible factors sets in and also due to the better intraoperative and postoperative care using latest agents so far approved for this purpose.
Most studies have demonstrated an immediate reduction in PAP and PVR, signifying a sudden drop in left atrial pressure and reversal of the severe spastic pulmonary vasoconstriction that accompanies left atrial hypertension in some patients [10& 14]. Others have shown slow regression of elevated PAP and PVR several months postoperatively [14]. These reports point toward the involvement of multiple factors in the development of PAH in mitral valve disease [14]. In our study the mean PAP and PVR did not fall significantly immediately following MVR. The mean fall in PAP was about 46.1mmHg in 1stmonth and 38.9 mmHg in the 3rd month follow up after surgery, which was against the previous views.
Reduction of PHT is not random after MVR and is found to be reducing gradually at 1 and 3 months in our study. This analysis showed that the reduction in PHT had a gradual course. This gives us a clue that the reduction in Pulmonary Hypertension is a gradual one and needed change in organic level as well as in the dynamic level which takes some time to achieve [15-20].
However, the long-term follow up of these patients are needed to conclude firmly regarding reduction of PHT postoperatively.