A Long-term Follow-up Study In HOCM Patients After Percutaneous Transluminal Septal Myocardial Ablation Therapy

[Objective]:To evaluate the long-term efficiacy of percutaneous transluminal septal ablation (PTSMA) in patients with obstructive cardiomyopathy (HOCM) and the effection of medication treatment to left ventricular structure and left ventricular outflow tract pressure gradient (LVOTPG),to evaluate the accuracy of transthoracic Doppler echocardiography (TDE) quantitatly estimating of left ventricular outflow tract pressure gradient (LVOTPG).[Method]:The study is divided into two steps below:The first step:All the HOCM patients with PTSMA during January2005to October2013in the First Affiliated Hospital of Kunming Medical University underwent TDE examination and LVOTPG determinnated a week before the operation.LVOTPG were measured by catheter again during the operation to evaluate the accuracy and correlation of these two methods for further research.Step Two:A retrospective study from January2005to October2013in the First Affiliated Hospital of Kunming Medical University and diagnosed with HOCM, while all the25patients had the PTSMA operated on. All the patients were followed up for1-24months, the average17.00±8.20months,included the change of clinical symptoms, postoperative medication case, LVOTPG, cardiac structure (LAD, section thickness IVS base, LVOTD) and left ventricular ejection fraction (EF%value).[Results]: 1. LVOTPG measured by TDE is36-240mmHg, averaged120.36±50.50mm Hg; left heart catheter measurements LVOTPG for39-245mmHg, averaged (120.48±49.28) mm Hg. Pearson correlation analysis showed highly relevant to the two methods from the LVOTPG (r=0.886, P<0.001). Analysis on the application of Bland-Altman method of TDE and left heart catheterization measuring LVOTPG, the95%confidence interval inside (-51.10-50.91mmHg), only2cases are beyond the limits of consistency interval.More than10mmHg overestimated in2cases (8%) and underestimated more than10mmHg in3cases (12%) by TDE; the degree of variability of the observed values for41.95%. The extent of LVOTPG overestimated by TDE averaged13.52±2.11mm Hg, the extent of underestimated averaged (13.70±2.50) mm Hg. The extent of overestimated and underestimated of LVOTPG by TDE was no significant difference (P=0.903). The results showed that, the measurement of LVOTPG by TDE is an important and effective non-invasive inspection approach.2.All the HOCM patients with PTSMA immediately LVOTPG is3-78mmHg decreased significantly compared with preoperative [(29.16±18.70) mm Hg and preoperative (120.48±49.28) mm Hg, P<0.01]. On postoperative patients (One patient died from acute myocardial infarction4hours after ablation) to track follow-up1-24months, averaged17.00±8.20a month; The symptoms with obstructive of the24cases were lessened or disappeared after operation, significantly improved quality of life compared with the preoperative.The average LAD, the average IVS basement paragraph thickness, the average LVOTD, and the average LVOTPG showed a gradually improved trend, and their changes still had statistics meaning in24months postoperative (respectively and1-3months or6months postoperative comparison, P<0.05or P<0.01); the average left ventricular ejection fraction (EF%value) obviously declined within2week (P<0.01),1-3months after increased to near preoperative level1(P>0.05), no significant change within24months after operation (P>0.05).Whether to continue to taking β-blockers and (or) calcium antagonists or disopyramide, all the patients were divided into two groups. Taken on2groups of postoperative follow-up of TDE. From the two groups of contrast, curves in the whole, there were no significant differences between the regular medication postoperative group and not regular medication group except the average LVOTPG. The regular medication group was no obvious change untill3months later in addition to the average left ventricular ejection fraction (EF%value),the other indexes showed a trend of gradually improving and the changes still have statistical significance in24months after the operation(6months,12months and24months after operation compared with the1-3months after operation, P<0.05or P<0.01); while except the average LVOTD of not regular medication group still had changes untill12months (compared with the12months after operation, P<0.05), others had no significant change after3months(compared with the1-3months after the operation, P<0.05).[Conclusion]:1、The LVOTPG estimated by TDE was highly correlated with that measured by left heart catheter, TDE can be used as the main noninvasive method to diagnize left ventricular outflow tract obstruction,but it can not completely replace left heart catheterization.2、The average LAD,the average thickness of IVS basal segment,the average LVOTD and the average LVOTPG have a gradually improved trend, the average LAD get improvement in2weeks after operation;the others get apparent improvement in2weeks to3months postoperative.All these improvement continued to the end of follow-up after operation.3、The left ventricular ejection fraction (EF%value) decreased significantly in2weeks postoperation, but it recovered near to preoperative levels after1-3months and no apparent difference compared with preoperation; there was no significant changes happened until24months.4、The average LAD, the average IVS basal segment thickness, the average LVOTD and the average LVOTPG of the regular medication group showed a gradually improve trend, and it continued to the end of follow-up; While in not regular medication group these parameters were no significant difference after3months postoperative except the average LVOTD,it was improvement continued to12months postoperative. Therefore, the research shows that the regular postoperative medication curative effect may be better than not regular medication group.5、TDE is a useful method to find HOCM patients and to monitor PTSMA duing operation,and to postoperative evaluate operation effection.6、PTSMA is a effective treatment in patients with HOCM and effective minimalinvasive approach, but because it is a destructive operation, the risks should be strictly controlled.