Jorge Yarzebski

Patient delay and receipt of thrombolytic therapy among patients with acute myocardial infarction from a community-wide perspective

The duration of patient delay from the time of onset of symptoms of acute myocardial infarction (AMI) to hospital presentation, and the relation of delay time and various patient characteristics to receipt of thrombolytic therapy were examined as part of a community-based study of patients hospitalized with AMI in the Worcester, Massachusetts, metropolitan area. In all, 800 patients with validated AMI hospitalized at 16 hospitals in the Worcester metropolitan area in 1986 and 1988 constituted the study sample. Patients delayed on average 4 hours between noting symptoms suggestive of AMI and presenting to area-wide emergency departments with no significant change observed between 1986 and 1988. The shorter the time interval of delay, the greater the likelihood of receiving thrombolytic therapy; patients arriving at the emergency department within 1 hour of the onset of acute symptoms were approximately 2.5 and 6.5 times more likely to receive thrombolytic agents than were those presenting to the hospital between 4 and 6, and greater than 6 hours, respectively, after the onset of symptoms. Results of a multivariate analysis showed increasing length of delay, older age, history of hypertension or AMI and non-Q-wave AMI to be significantly associated with failure to receive thrombolytic therapy.

Outcomes and early revascularization for patients ≥65 years of age with cardiogenic shock☆

Hospital survival of patients with acute myocardial infarction (AMI) complicated by cardiogenic shock has improved during recent years. It is unclear whether this mortality benefit also applies to elderly patients with cardiogenic shock. Elderly residents (age > or = 65 years) of the Worcester, Massachusetts metropolitan area (1990 census population = 437,000) hospitalized with confirmed AMI and cardiogenic shock in all metropolitan Worcester, Massachusetts hospitals between 1986 and 1997 constituted the sample of interest. We examined the use of coronary reperfusion strategies, adjunctive therapy, and hospital mortality in a cohort of 166 cardiogenic patients treated early in the reperfusion era (1986 to 1991) compared with 144 patients with AMI treated approximately 1 decade later (1993 to 1997). There was a significant increase in the use of an early revascularization strategy over time (2% vs 16%, p <0.001). Marked increases in use of antiplatelet therapy, beta blockers, and angiotensin-converting enzyme inhibitors were also observed over the decade-long experience. In-hospital case fatality declined significantly over time, from 80% (1986 to 1991) to 69% (1993 to 1997) in elderly patients who developed cardiogenic shock (p = 0.03). After adjusting for differences in potentially confounding prognostic characteristics between patients hospitalized in the 2 study periods, an even more pronounced reduction in hospital mortality (42%) was observed for the most recently hospitalized cohort. The most powerful predictor of in-hospital survival was use of an early revascularization approach to treatment. Thus, hospital mortality has declined for patients > or = 65 years of age with AMI complicated by cardiogenic shock, and this decline has occurred in the setting of broader use of early revascularization and adjunctive medical therapy for this high-risk population.

T2 and T3 sympathetic ganglia in the adult human: a cadaver and clinical-radiographic study and its clinical application

The technique of percutaneous radiofrequency (RF) upper thoracic sympathectomy mandates an exact knowledge of the anatomical location of the sympathetic ganglia. Because conflicting descriptions are given in anatomy texts, we examined the T2 and T3 sympathetic ganglia in 48 sympathetic chains in adult cadavers to measure the exact location of the ganglia. Measurements were made relative to their distances (a) dorsal to the ventral surface of the vertebral body and (b) rostral or caudal to the midpoint of the vertebral body. Median locations of T2 and T3 ganglia were 17 to 20 mm dorsal to the ventral surface of the vertebral body and 2 mm rostral to the T1-T2 and T2-T3 vertebral bodies. The sympathetic chains lay lateral to and between the heads of the ribs at these levels. A clinical-radiographic correlation study of the sympatholytic effectiveness of various needle electrode placement sites during sympathectomy confirmed these findings. These data have been used to modify the technique of percutaneous RF sympathectomy.

Ten-year trends in the incidence, treatment, and outcome of Q-wave myocardial infarction.

The benefits of coronary reperfusion and antiplatelet therapy for patients with Q-wave acute myocardial infarction (Q-AMI) are well established in the context of randomized, controlled trials. The use and recent impact of these and other therapies on the broader, community-wide population of patients with Q-AMI is less well established. Residents of the Worcester, Massachusetts, metropolitan area (1990 census population 437,000) hospitalized with confirmed Q-AMI in all metropolitan Worcester, Massachusetts, hospitals in 4 1-year periods between 1986 and 1997 comprised the sample of interest. We examined the rates of occurrence, use of reperfusion strategies, and hospital mortality in a cohort of 711 patients with Q-AMI treated early in the reperfusion era (1986 and 1988) in comparison to 669 patients with Q-AMI treated a decade later (1995 and 1997). The percentage of Q-AMI among all hospitalized patients with AMI decreased over the decade of reperfusion therapy: 52% in 1986 and 1988 versus 35% in 1995 and 1997 (p < 0.001). Use of reperfusion therapy for patients with Q-AMI increased from 22% to 57%, with a marked increase in the use of primary angioplasty over time (1% vs 16%). The profile of patients receiving reperfusion therapy also changed significantly over the study period. Marked increases in use of antiplatelet therapy, beta blockers, angiotensin-converting enzyme inhibitors, and decreased use of calcium channel blockers, were observed over time. The crude in-hospital case fatality rate declined from 19% (1986 and 1988) to 14% (1995 and 1997) in patients with Q-AMI. Results of a multivariable regression analysis showed lack of reperfusion therapy, older age, anterior wall AMI, and cardiogenic shock to be independent predictors of in-hospital mortality in patients with Q-AMI. Thus, the percentage of all AMIs presenting as Q-AMI, and hospital mortality after Q-AMI, has decreased significantly in the past 10 years. The decrease in mortality occurs in the setting of broader use of reperfusion and adjunctive therapy (including primary angioplasty).

Erroneous measurement of intracranial pressure caused by simultaneous ventricular drainage: a hydrodynamic model study

Intracranial pressure (ICP) is often measured from intraventricular catheters, a technique that allows therapeutic drainage of ventricular cerebrospinal fluid (CSF) as an aid in controlling ICP and circumventing obstruction. Drainage of CSF simultaneously with ongoing ICP measurement has been advocated as safe and efficient, and devices are commercially available to permit this practice; however, this concept has been seriously challenged, based on clinical observations. The inaccuracy induced by simultaneous CSF drainage and ICP monitoring is quantitated in this report in a mechanical brain model using a standard ventricular catheter. The following conclusions have been confirmed: 1) rapid CSF drainage induces a severe artifactual reduction in measured ICP, more extreme at higher pressures; 2) calibrated slower rates of CSF drainage produce a severe, although less immediate, reduction in measured ICP; 3) severe artifact appears even in the presence of continuous CSF outflow, so a system that measures ICP only in the presence of CSF flow does not prevent artifact; 4) with simultaneous CSF drainage, measured ICP is determined more by the outflow pressure setting than by actual brain pressure; 5) Since ICP elevation of 25 to 30 mm Hg blocks CSF production, even slow fluid drainage at high pressures should ultimately lead to ventricular collapse and severe artifact.