Biomedical subjects

Keith G Buchan

Publications and source records attributed to Keith G Buchan.

6 recordsLinked to original sources

PubMed2006

Relationship between postoperative cardiac troponin I levels and outcome of cardiac surgery.

BACKGROUND: Cardiac surgery may be associated with significant perioperative and postoperative morbidity and mortality. Underlying pathology, surgical technique, and postoperative complications may all influence outcome. These factors may be reflected as a rise in postoperative troponin levels. Interpretation of troponin levels in this setting may therefore be complex. This study assessed the prognostic significance of such measurements, taking into account potential confounding variables. METHODS AND RESULTS: One-thousand three hundred sixty-five patients undergoing cardiac surgery underwent measurement of cardiac troponin I (cTnI) at 2 and 24 hours after surgery. The relationship of these measurements to subsequent mortality was established. After taking into account all other variables, cTnI levels measured at 24 hours were independently predictive of mortality at 30 days (odds ratio [OR] 1.14 per 10 microg/L, 95% confidence interval [CI] 1.05 to 1.24, P=0.002), 1 year (OR 1.10 per 10 microg/L, 95% CI 1.03 to 1.18, P=0.006), and 3 years (OR 1.07 per 10 microg/L, 95% CI 1.00 to 1.15, P=0.04). Cardiac TnI levels in the highest quartile at 24 hours were associated with a particularly poor outcome. CONCLUSIONS: cTnI levels measured 24 hours after cardiac surgery predict short-, medium-, and long-term mortality and remain independently predictive when adjusted for all other potentially confounding variables, including operation complexity.

Aged↗

PubMed2006

Renal function and outcome from coronary artery bypass grafting: impact on mortality after a 2.3-year follow-up.

BACKGROUND: Severe renal dysfunction is associated with a worse outcome after coronary artery bypass graft surgery (CABG). Less is known about the effects of milder degrees of renal impairment, and previous studies have relied on levels of serum creatinine, an insensitive indicator of renal function. Recent studies have suggested that estimated glomerular filtration rate (eGFR) is a more discriminatory measure. However, data on the utility of eGFR in predicting outcome from CABG are limited. METHODS AND RESULTS: We studied 2067 consecutive patients undergoing CABG. Demographic and clinical data were collected preoperatively, and patients were followed up a median of 2.3 years after surgery. Estimated GFR was calculated from the Modification of Diet in Renal Disease equation. The primary outcome was all-cause mortality. Mean+/-SD eGFR was 57.9+/-17.6 mL/min per 1.73 m2 in the 158 patients who died during follow-up compared with 64.7+/-13.8 mL/min per 1.73 m2 in survivors (hazard ratio [HR], 0.71 per 10 mL/min per 1.73 m2; 95% CI, 0.64 to 0.80; P<0.001). Estimated GFR was an independent predictor of mortality in both models with other individual univariable predictors (HR, 0.80 per 10 mL/min per 1.73 m2; 95% CI, 0.72 to 0.89; P<0.001) and the European system for cardiac operative risk evaluation (HR, 0.88 per 10 mL/min per 1.73 m2; 95% CI, 0.78 to 0.98; P=0.02). CONCLUSIONS: Estimated GFR is a powerful and independent predictor of mortality after CABG.

Aged↗

PubMed2006

Primary malignant melanoma: a rare cause of mediastinal mass.

A case of primary malignant melanoma in the mediastinum presenting as recurrent laryngeal nerve palsy is reported. Tissue biopsy at mediastinotomy yielded a diagnosis of malignant melanoma. The mass was fixed to the left aspect of the trachea and to the upper border of the left main bronchus and could not be removed surgically. Further extensive clinical and radiological investigations revealed no evidence of tumor elsewhere in the body.

Diagnosis, Differential↗

PubMed2006

Bilateral cervical lung hernia with T1 nerve compression.

Lung hernia is a rare condition. Approximately one third of cases occur in the cervical position. We report a case of bilateral cervical lung hernia associated with neuralgic pain that was repaired using bovine pericardium and biological glue.

Adult↗

PubMed2006

Mitral valve repair: an in-vitro comparison of the effect of surgical repair on the pressure required to cause mitral valve regurgitation.

BACKGROUND AND AIM OF THE STUDY: The study aim was to compare mitral valve repair techniques in vitro. Rupture or elongation of the mitral valve chordae tendineae is a known cause of mitral regurgitation, and can be corrected by edge-to-edge repair, chordal replacement, or chordal transposition. METHODS: A test apparatus was used to apply pressure to porcine mitral valves. Mitral valve specimens were tested intact (n = 50), after they had been experimentally damaged, and after repair. Each test was repeated ten times. Experimental damage consisted of severing either the anterior leaflet strut, and attached marginal chordae (n = 30) or posterior leaflet chordae (n = 20). Valves with damaged anterior leaflets were repaired by either: (i) edge-to-edge repair; (ii) chordal replacement; or (iii) chordal transposition. Valves with damaged posterior leaflets were repaired by the first two techniques. Each repair method was repeated on ten specimens. RESULTS: Mitral valves repaired using the edge-to-edge repair (p = 0.002) and chordal replacement (p = 0.038), after rupture to anterior leaflet chordae, recovered significantly better than specimens repaired by chordal transposition. There was no statistical difference in recovery between edge-to-edge repair and chordal replacement (p > 0.05). There was no statistical difference (p > 0.05) in the recovery of the pressure withstood by valves repaired by edge-to-edge repair and chordal replacement, after rupture of posterior leaflet chordae. CONCLUSION: These results showed that edge-to-edge repair and chordal replacement are well suited for the repair of both the anterior and posterior leaflets.

Animals↗

PubMed2005

The role of Chordae tendineae in mitral valve competence.

BACKGROUND AND AIM OF THE STUDY: The study aim was to understand the role of different mitral valve chordae tendineae, and how damage to them affects valve competence. METHODS: A test apparatus was used to apply pressure to porcine mitral heart valves that were intact and have had selected chords severed. Anterior leaflet strut and marginal chords were selectively severed, as were posterior leaflet basal and marginal chords. Commissural chords were also severed. RESULTS: Severing anterior leaflet marginal chords (p = 0.018) and commissural chords (p = 0.018) significantly reduced mitral valve competence. Severing posterior leaflet marginal and basal chords, and anterior leaflet strut chords, had no significant effect in reducing the pressures that the valves could withstand. Severing a mixture of posterior leaflet basal and marginal chords significantly reduced the pressure withstood by the valves (p = 0.004). CONCLUSION: The study results confirmed that anterior leaflet marginal chords, but not strut chords, are vital for valve competence. Commissural chords were also shown to be vital for mitral valve competence. Several posterior leaflet chords had to be severed to affect mitral valve competence.

Animals↗