The early multicenter experience suggests that this stent is a useful adjunct to coronary angioplasty to prevent or minimize complications associated with flow-limiting coronary artery dissections previously correctable only by surgery. Although this study was not randomized, it demonstrated a high technical success rate and encouraging results with respect to the low incidence of emergency coronary artery bypass graft surgery and myocardial infarction.

Myocardial perfusion pressure, defined as the aortic diastolic pressure minus the right atria1 diastolic pressure, correlates with coronary blood flow during cardiopulmonary resuscitation (CPR) and predicts initial resuscitation success. Whether this hemodynamic parameter can predict 24-h survival is not known. We examined the relationship between myocardial perfusion pressure and 24-h survival in 60 dogs that underwent prolonged (20 min) ventricular fibrillation and CPR. Forty-two (70%) animals were initially resuscitated and 20 (33%) survived for 24 h. Myocardial perfusion pressure was significantly greater when measured at 5, 10, 15 and 20 min of ventricular fibrillation in the resuscitated animals than in the non-resuscitated animals (P < 0.01). Likewise, the myocardial perfusion pressure was also greater in the animals that survived 24 h than in animals that were resuscitated, but died before 24 h (P < 0.02). Myocardial perfusion pressure measured after 10 min of CPR was 11  2 mmHg in animals never resuscitated, 20  3 mmHg in those resuscitated that died before 24 h and 29  2 mmHg in those that survived 24 h (P < 0.05). A myocardial perfusion pressure at 10 min of CPR of 20 mmHg or less is an excellent predictor of poor survival (negative predictive value = 96%). Myocardial perfusion pressure is a useful index of CPR effectiveness and therefore may be a useful guide in helping to optimize resuscitation efforts.

This study was conducted to investigate the importance of the depth of chest compression in producing effective cardiopulmonary resuscitation (CPR) in animals, as indicated by cardiac output and mean arterial blood pressure. Cardiac output was measured by a modified indicator dilution technique in 8 anesthetized dogs, 6 to 12 kg body weight, during repeated 2-minute episodes of electrically induced ventricular fibrillation and CPR provided by a mechanical chest compressor and ventilator (Thumper ® ). Chest compression exceeding a threshold value (x0) between 1.5 and 3.0 cm was required in each animal to produce measurable cardiac output. In particular, cardiac output (CO) was linearly related to chest compression depth (x) by an expression of the form CO = a(x-x0) for x > x0, and CO = 0 for x  x0. The mean value of x0 was 2.3 cm. A similar threshold for measurable blood pressure was observed in 7 of the 8 dogs, with a mean value of 1.8 cm. For chest compression of 2.5 cm or greater, relatively modest increases in chest compression depth caused relatively large changes in cardiac output.

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