Triaging Primary Care Patients Referred for Chest Pain to Specialist Cardiology Centres: Efficacy of an Optimised Protocol

INTRODUCTION

Patients referred for chest pain from primary care have increased, along with demand for outpatient cardiology consultations. We evaluated 'Triage Protocol' that implements standardised diagnostic testing prior to patients' first cardiology consultation.

MATERIALS AND METHODS

Under the 'Triage Protocol', patients referred for chest pain were pretriaged using a standardised algorithm and subsequently referred for relevant functional diagnostic cardiology tests before their initial cardiology consultation. At the initial cardiology consultation scheduled by the primary care provider, test results were reviewed. A total of 522 triage patients (mean age 55 ± 13, male 53%) were frequency-matched by age, gender and risk cohort to 289 control patients (mean age: 56 ± 11, male: 52%). Pretest risk of coronary artery disease was defined according to a Modified Duke Clinical Score (MDCS) as low (<10), intermediate (10-20) and high (>20). The primary outcome was time from referral to diagnosis (days). Secondary outcomes were total visits, discharge rate at first consultation, patient cost and adverse cardiac outcomes.

RESULTS

The 'Triage Protocol' resulted in shorter times from referral to diagnosis (46 vs 131 days; P <0.0001) and fewer total visits (2.4 vs 3.0; P <0.0001). However, triage patients in low-risk groups experienced higher costs due to increased testing (S$421 vs S$357, P = 0.003). Adverse cardiac event rates under the 'Triage Protocol' indicated no compromise to patient safety (triage vs control: 0.57% vs 0.35%; P = 1.000).

CONCLUSION

By implementing diagnostic cardiac testing prior to patients' first specialist consultation, the 'Triage Protocol' expedited diagnosis and reduced subsequent visits across all risk groups in ambulatory chest pain patients.

Astragalus membranaceus and Polygonum multiflorum protect rat heart mitochondria against lipid peroxidation

We isolated rat heart mitochondria and induced lipid peroxidation with ADP and FeSO4. Oxygen consumption and MDA formation were measured for quantitating the amount of lipid peroxidation. Using these methods, we screened the water extracts of 14 Chinese medicinal herbs for their effect on lipid peroxidation. It was found that Astragalus membranaceus inhibited 42.1 +/- 3.4% of oxygen consumption and 39.8 +/- 3.2% of MDA production at concentration of 2 mg dried herb/ml mitochondrial suspension. At the same concentration, Polygonum multiflorum inhibited 52.1 +/- 7.3% of oxygen consumption and 50.9 +/- 5.3% of MDA production. Other herbs did not inhibit lipid peroxidation to 50% of control at concentration up to 6 mg dried herb/ml mitochondrial suspension. Purification and identification of the active component(s) in Astragalus membranaceus and Polygonum multiflorum as well as their clinical application await further studies.

Some properties of the millimolar Ca2+-dependent proteinase from bovine cardiac muscle

Three to six mg of the millimolar Ca2+-requiring proteinase (m-calpain) were obtained from 1 kg bovine cardiac muscle (fresh wt) and some enzymatic properties of this proteinase were determined. Activity of bovine cardiac m-calpain decreases as ionic strength increases from 75 to 1000 mM. Maximal activation of m-calpain by Ca2+, La3+, Ba2+, and Mn2+ occurs at 2 to 3 mM concentrations of each of these divalent cations, but La3+ activation is only 20 to 25% and Ba2+ and Mn2+ activation only 6 to 10% as great as Ca2+ activation. Maximum Sr2+ activation occurs at 20 mM Sr2+ and is 90 to 95% of maximum Ca2+ activation. Mg2+, Zn2+, Cr2+, and Cd2+ do not activate m-calpain when added alone; Mg2+ does not affect, but Zn2+ inhibits, Ca2+-stimulated activity. The nonionic detergents, Triton X-100 and Brij 35, activate m-calpain 1.6- to 2.0-fold but do not change its Ca2+ requirement. Sodium dodecyl sulfate and urea inhibit m-calpain completely at 0.045% and 2.0 M, respectively. Because they bind Ca2+ needed for activation, ATP, ADP, and ITP inhibit m-calpain. The trypsin inhibitors, phenylmethylsulfonyl fluoride, ovomucoid trypsin inhibitor, ovoinhibitor, aprotinin, alpha 1-antiproteinase inhibitor, soybean trypsin inhibitor, and lima bean trypsin inhibitor do not affect m-calpain activity; m-calpain does not release measureable quantities of acid-soluble peptides from a rabbit skeletal sarcoplasmic protein fraction but does degrade rabbit skeletal myofibrils and casein.