Intrapulmonary artery balloon pulsation improves circulatory function after acute myocardial infarction in pigs.

AIM: To examine whether pulmonary artery balloon pulsation (PABP) could improve circulatory function in acute myocardial infarction (AMI) in pigs. METHODS/RESULTS: Ten downsize pigs were sedated and ventilated. AMI was induced by inserting a plug into the left anterior descending artery. A pulsation balloon was placed in the pulmonary artery in all animals. In the treatment group (TG), pulsations began when life-threatening arrhythmia or > 30% drop in mean blood pressure (MBP) or > 40% decrease in cardiac output compared to baseline occurred. Pulsation rate was 120/min, independent of the heartbeat, maintained for 10 min. The control group (CG) received no pulsation. In the TG (n = 5), mean BP after the AMI improved by 7 ± 12 mmHg after 150 min while in the CG, MBP decreased by 17 ± 25 mmHg, P < 0.05; coronary perfusion pressure improved by 8 ± 7 mmHg in the TG but decreased by 15 ± 12 in the CG (P < 0.05). In the CG, cardiac output did not change but in the TG it improved from 3.5 ± 0.9 after the AMI to 4.2 ± 1.1 l/min 150 min after AMI (P < 0.05). The TG required 1.8 ± 0.4 electric shocks for ventricular fibrillation versus 0.8 ± 0.4 in the pulsation group (P < 0.05). CONCLUSION: PABP could be useful in the management of AMI due to improved mean arterial BP, coronary perfusion pressure, cardiac output and electrical stability. The mechanism of this effect remains to be determined.

Ultrasound assessment of ocular vascular effects of repeated intravitreal injections of ranibizumab for wet age-related macular degeneration.

PURPOSE: Determine the effect of repeated intravitreal injections of ranibizumab (0.5 mg; 0.05 ml) on retrobulbar blood flow velocities (BFVs) using ultrasound imaging quantification in twenty patients with exudative age-related macular degeneration treated for 6 months. METHODS: Visual acuity (ETDRS), central macular thickness (OCT), peak-systolic, end-diastolic and mean-BFVs in central retinal (CRA), temporal posterior ciliary (TPCA) and ophthalmic (OA) arteries were measured before, 2 days, 3 weeks and 6 months after the first injection. Patients were examined monthly and received 1-5 additional injections depending on ophthalmologic examination results. RESULTS: Six months after the first injection, a significant increase in visual acuity 50.9 ± 25.9 versus 44.4 ± 21.7 (p < 0.01) and decrease in mean central macular thickness 267 ± 74 versus 377 ± 115 µm (p < 0.001) were observed compared to baseline. Although mean-BFVs decreased by 16%±3% in CRA and 20%±5% in TPCA (p < 0.001) 2 days after the first injection, no significant change was seen thereafter. Mean-BFVs in OA decreased by 19%±5% at week 3 (p < 0.001). However, the smallest number of injections (two injections) was associated with the longest time interval between the last injection and month 6 (20 weeks) and with the best return to baseline levels for mean-BFVs in CRA, suggesting that ranibizumab had reversible effects on native retinal vascular supply after its discontinuation. Moreover, a significant correlation between the number of injections and percentage of changes in mean-BFVs in CRA was observed at month 6 (R = 0.74, p < 0.001) unlike TPCA or OA. CONCLUSION: Ranibizumab could impair the native choroidal and retinal vascular networks, but its effect seems reversible after its discontinuation.