Balloon aortic valvuloplasty in contemporary practice.

BACKGROUND: There has been a revival of balloon aortic valvuloplasty (BAV) for severe aortic stenosis, as a result of an increasing number of patients undergoing trans-catheter aortic valve implantation (TAVI). However, there has not been universal adoption of BAV as a standalone, nor bridging therapy. METHODS: A retrospective analysis of the practice at our institution between June 2009 and May 2016 was performed. Demographic, clinical, procedural, and follow-up data on all patients were collected. RESULTS: A total of 200 patients with a median age of 82 years and severe symptomatic aortic stenosis underwent BAV from June 2009 to May 2016. All patients had appreciable comorbidity with a mean logistic Euro SCORE of 48 ± 11 and mean standard Euro SCORE 15 ± 4. BAV was performed for palliation in 118 (59%), as a bridging therapy for TAVI in 55 (27.5%) and bridging to surgical AVR in 27 patients (13.5%), respectively. Major complications occurred in 14 patients (7%) including 2 in-patient deaths (1%). A statistically significant improvement in symptoms and a decrease in trans-valvular gradient were observed. CONCLUSION: BAV is an effective treatment strategy, either as a bridge to definitive therapy or as a palliative procedure, with an acceptable mortality. BAV is associated with a significant improvement in symptoms and is valuable as a palliative treatment in high-risk patients, where no other invasive option is available.

Exercise training following myocardial infarction improves myocardial perfusion assessed by thallium-201 scintigraphy.

AIM: We assessed the effects of a 6-week exercise programme on the thallium-201 myocardial perfusion characteristics of patients following myocardial infarction. METHODS: Twenty-five patients presenting with a first acute myocardial infarction were randomised into two groups: (i) those undergoing a supervised exercise training programme over 6 weeks (n=15) and (ii) a control group who did not attend the exercise programme (n=10). All underwent three sequential stress thallium myocardial perfusion scans at 10 days, 6 weeks and 3 months after infarction. The stress conditions were identical on each occasion. The images were analysed using a polar plot with a computer assisted algorithm comparing stress and redistribution data. Values for extent, severity and percentage redistribution of the thallium images were generated. RESULTS: A total of 29 perfusion defects were identified, 18 in the exercise group and 11 in the control group. Over 3 months in the exercise group the mean extent of the stress image defect fell from 109+/-64 to 95+/-51 pixels (P<0.05) while in the control group there was an increase from 133+/-57 to 144+/-57 pixels (P=ns). Stress defect severity fell in the exercise group from 581+/-417 to 494+/-346 S.D. (P<0.05) but increased in the control group from 765+/-494 to 877+/-543 S.D. (P=ns). On redistribution imaging in the exercise group a significant decrease was observed in both extent (94+/-56 to 76+/-43 pixels (P<0.05)) and severity (541+/-387 to 438+/-291 S.D. (P<0.05)) of the defects. However in the control group no significant change was observed for extent (125+/-54 to 125+/-52 pixels) or severity (745+/-485 to 820+/-503 S.D.) of the redistribution defects (P=ns). Reversibility of the defects increased slightly in both the exercise group (from 14.6+/-17 to 17.5+/-20%) and the control group (5.2+/-5 to 9.6+10%) (P=ns). CONCLUSION: Following myocardial infarction a 6-week exercise programme improves myocardial perfusion characteristics. An exercise programme should be integrated into cardiac rehabilitation protocols for patients after infarction.

The histology of viable and hibernating myocardium in relation to imaging characteristics.

OBJECTIVES: This study characterizes the histology of myocardium predicted to be hibernating using three different imaging techniques to explain the discordance among them. BACKGROUND: Both radionuclide and functional imaging techniques were used to assess myocardial hibernation. The former have high sensitivity and the latter high specificity for predicting functional recovery. METHODS: Nineteen patients underwent thallium-201 and 99m-technetium tetrofosmin myocardial perfusion imaging, and dobutamine magnetic resonance imaging (MRI), prior to coronary bypass grafting. Criteria for predicted hibernation for each technique were defined before operation. Postoperative criteria for scar and true hibernation were also defined. Biopsies were analyzed for myocyte volume fraction (MVF), glycogen deposition and pathologic cell features. RESULTS: Thallium was most sensitive in predicting hibernation (88%) and MRI most specific (84%); and, although there was good agreement between thallium and tetrofosmin (85%), agreement between MRI and thallium (59%) or tetrofosmin (59%) was poor. For each technique, MVF was higher in segments predicted to be hibernating rather than scar (p < 0.05). The MVF was higher where both thallium and MRI predicted hibernation (0.77+/-0.07) than in segments predicted by thallium alone (0.69+/-0.13, p < 0.05). Proven hibernating segments had a higher MVF than scar (0.72+/-0.11 vs. 0.6+/-0.26, p < 0.05). CONCLUSIONS: Preservation of myocyte fraction is an important determinant of functional recovery after revascularization. A higher myocyte fraction is required to maintain contractile reserve than to achieve significant tracer uptake. This explains the higher sensitivity of radionuclide imaging compared with dobutamine MRI in the identification of myocardial hibernation.