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Biomedical subjects

R Kass

Publications and source records attributed to R Kass.

At least 19 recordsLinked to original sources
PubMed1999

Actual failure rates: A method of assessing tissue valve reoperation rates.

BACKGROUND: Patients older than age 70 with coronary disease undergoing mitral valve replacement have a limited survival rate, suggesting that few of these patients will require reoperation if they receive a tissue mitral valve. However, traditional actuarial analysis of valve durability censors patients who die before valve failure and doesn't reflect the lower frequency of reoperation in patient subgroups with limited survival rates. METHODS: Actual or cumulative reoperation rates represent the rates of reoperation in patients without censoring for death and estimate the risk that the valve will fail before the patient dies. The actual rates of valve rereplacement were determined in 255 recipients of tissue mitral valves, categorizing patients by age and presence of coronary artery disease at 8 years after surgery and compared with standard actuarial estimates of valve durability. RESULTS: Operative mortality rates were 17.5% for patients with coronary artery disease and 6.0% for those without (P <.001). At 8 years, the actual reoperation rates for patients younger than age 70 with and without coronary artery disease were 9.2% (n = 76) and 10% (n = 90), respectively. In patients older than age 70 without coronary artery disease the reoperation rate was 9.4% (n = 32). In contrast, the actual reoperation rate was only 1.7% (n = 58) in patients older than age 70 with coronary artery disease. This rate was significantly lower (P =.05) than the other groups. The difference in reoperation rates was not significant if standard actuarial analysis was used. CONCLUSIONS: Actual reoperation rates are significantly lower in patients older than 70 years with CAD receiving mitral tissue valves than in younger patients or in patients without coronary artery disease. Calculation of actual reoperation rates provides a unique and clinically useful perspective in evaluating data on prosthetic valve reoperation rates.

Age Factors↗
PubMed1996

Clinical experience with one hundred consecutive patients undergoing orthotopic heart transplantation with bicaval and pulmonary venous anastomoses.

OBJECTIVE: Our objective was to assess survival, need for pacemaker insertion, and rejection frequency with a new surgical technique of orthotopic heart transplantation using bicaval and pulmonary venous anastomoses. METHODS: We retrospectively reviewed 100 consecutive patients who had orthotopic heart transplantation with this technique between July 1991 and September 1995. RESULTS: The mean age was 57.0 +/- 11.1 years, with 51 patients being 60 years or older. The mean donor/recipient weight ratio was 0.92, and in 28 patients the ratio was less than 0.8. The early (30-day) survival was 100% and the 1- and 2-year survivals were 98% +/- 2% and 96% +/- 2%, respectively. Survival was not affected by age or by the duration of the OKT3 therapy (p > 0.2 for each of these parameters). The seven late deaths were due to infection (n = 2), graft atherosclerosis (n = 3), acute rejection (n = 1), and nonspecific graft failure (n = 1). No permanent pacemaker was required in the first 6 months after the operation, and all the patients were discharged in normal sinus rhythm. Freedom from treated rejection was significantly greater in patients with 7 days of OKT3 therapy than in patients with 14 days of therapy (p < 0.0001). CONCLUSIONS: Orthotopic heart transplantation with bicaval and pulmonary venous anastomoses offers an improved alternative to the standard biatrial technique, with a 30-day mortality of 0,% in 100 consecutive patients, excellent intermediate-term survival, and elimination of the need for pacemaker insertion. More normal anatomic configuration and synchronous function of the atria may have contributed to these results.

Adolescent↗
PubMed1995

Australian Case-Control Study of Adverse Reactions to Japanese Encephalitis Vaccine.

Background: Japanese encephalitis (JE) is widely distributed in Asia and is the world's most common aborviral encephalitis. An effective vaccine against JE has been used in Asia for decades without reports of serious adverse reactions. Since 1989, an apparent increase in frequency of allergic reactions to JE vaccine has been reported from a number of nonendemic countries, including Australia. The objective of this study was to evaluate possible risk factors for allergic reactions associated with Japanese encephalitis (JE) vaccine. Methods: A case-control study was carried out in Australia. Subjects were persons who had developed an allergic reaction (rash and/or edema) that had occurred within 1 week of a dose of Biken JE vaccine. All cases had been reported to the Australian Adverse Reactions Advisory Committee, and all could be accessed for purposes of this study. Three matched controls were recruited for each of five cases. Participants completed a questionnaire and had venous blood drawn. Results: Cases were significantly less likely than controls to give a history of contact with dogs (Fisher's exact test p =.03); were more likely than controls to have received other immunizations in the 1-9 days prior to, rather than on the same day, as the JE vaccine (chi-square test for independence p =.015); and were more likely than controls to have consumed more than usual quantities of alcohol in the 48 hours following the last dose of JE vaccine (Fisher's exact test p =.034). Conclusions: We recommend, where possible, that JE vaccine be administered concurrently with other vaccines, that recipients be advised to avoid more than usual alcohol intake after receiving JE vaccine, and that active surveillance of adverse events associated with JE vaccine be conducted.

Journal Article↗