Whole cycle non-hyperaemic pressure ratios have better stability than diastolic ratios after percutaneous coronary intervention due to changes in diastolic coronary haemodynamics

Background

Post percutaneous intervention (PCI) fractional flow reserve (FFR) value of ≥0.90 is an accepted marker of procedural success, and similarly, a cut-off of ≥0.95 has recently been proposed for post-PCI instantaneous wave free ratio (iFR). However, the stability of non-hyperaemic pressure ratios (NHPRs) and microcirculatory resistance post-PCI, is not well characterised. as submaximal hyperaemia post-PCI may affect them.

Purpose

We performed this study to assess stability and reproducibility of NHPRs measured immediately post-PCI and repeated at 30 minutes post-PCI.

Methods

Seventy-seven patients undergoing pressure wire guided PCI (age 63.77±10.67 years, male 71%,) had haemodynamic assessment done immediately post-PCI and after a recovery period 30 minutes (Figure A, B). Manual offline analysis was performed to derive resting pressure ratios during whole cycle: average ratio of distal coronary pressure to proximal aortic pressure at rest (Pd/Pa) and resting full cycle ratio (RFR); and during diastolic phase: average diastolic pressure ratio (dPR) and mathematically calculated iFRmat, measured by average Pd/Pa during wave free period (WFP) (from 25% into diastole until 5 msec before the end of diastole). We also measured coronary flow velocity by thermo-dilution time (Tmn) and basal microvascular resistance (BMR = Pa × Tmn × [(Pd − Pw) / (Pa − Pw)] baseline) corrected for coronary wedge pressure (Pw). Test-retest statistics was performed between NHPRs values immediately post-PCI and at 30 minutes. Moreover, crossover of NHPRs across the cut-off value of 0.95 was analysed to assess clinical utility of these indices for procedural success. p value of <0.05 was deemed statistically significant.

Results

There were no differences in the baseline characteristics of the study patients. Sub-maximal hyperaemia was demonstrated by Tmn of 0.54 sec (0.32, 0.75) immediately post-PCI which settled by 30 minutes, Tmn of 0.67 sec (0.43, 0.91), p=0.01 (Figure C). The median BMR increased from 49.25 mmHg sec (32.74, 61.61) to 59.60 mmHg sec (39.24, 76.91) at 30 minutes, p=0.04 (Figure D). Despite this, there were no significant differences in the values of resting whole cycle ratios (Pd/Pa and RFR) as well as diastolic ratios (dPR and iFRmat), with whole cardiac cycle NHPRs having best stability post-PCI (Table). Furthermore, crossover above or below the cut-off value of 0.95 occurred in approximately 1 in 5 diastolic NHPRs measurements but was three-fold lower for whole cycle NHPRs.

Conclusion

NHPRs remain stable post-PCI, despite submaximal hyperaemia being detected and may legitimately be used immediately post-PCI to determine procedural success. However, the test-retest reproducibility and clinical utility of diastolic NHPRs (dPR and iFR) was inferior to whole cycle NHPRs (Pd/Pa and RFR).

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): NIHR

How sweet is the pacemaker?

Pacemaker infections can be difficult to diagnose, especially when they present with non-specific symptoms and signs a long time after insertion of the device. Unidentified or partially treated low-grade chronic sepsis can result in multisystem disease processes with significant mortality and morbidity. Therefore, a high index of suspicion is required to identify the pacemaker as the source of sepsis and treat it effectively. This report describes a case of chronic pacemaker wire infection, which eventually presented with Sweet's syndrome, a rare manifestation of infective endocarditis.

Attitudes of 'tomorrow's doctors' towards psychiatry and mental illness

BACKGROUND

Attitudes to psychiatry and mental illness among medical undergraduates are key factors in determining their choice of psychiatry as a career and willingness to deal with psychiatric disorders in general practice.

METHODS

The responses of 108 medical students from the first and fourth year batches not exposed to psychiatry were compared with those of 139 final year students and interns who had completed varying components of psychiatric training using validated questionnaires that assessed their attitudes to psychiatry and mental illness, and their interest in psychiatry as a career choice.

RESULTS

A greater proportion of students exposed to psychiatric training endorsed positive attitudes to mental illness than those not exposed (odds ratio=0.4; 95% confidence intervals: 0.21-0.71; p=0.002). The overall attitude towards psychiatry did not differ between students before or after psychiatric education. Women students were more likely to consider a career in psychiatry (odds ratio=2.9; 95% confidence intervals: 1.36-6.21; p = 0.004), but the proportion of students of either gender wishing to pursue psychiatry as a career option did not differ significantly with psychiatric training.

CONCLUSION

Psychiatric education positively influences the attitudes of medical students towards mental illness and some aspects of psychiatry but does not increase the number of students wishing to pursue psychiatry as a career. Urgent and radical changes in psychiatric education for undergraduate medical students are required to meet current and future requirements of medical personnel trained to deal with psychiatric disorders.

The validation of the Tamil version of the 12 item general health questionnaire

The 12 item General Health Questionnaire (GHQ-12), increasingly used to screen for common mental disorders (CMD) in primary care, has been validated in different languages and cultures. However, the validity of the Tamil version has not been established. Consecutive patients, attending a primary health care centre in Vellore, rural Tamil Nadu, India, were screened for CMD using the Tamil version of the GHQ-12. The subjects were also interviewed using the Revised Clinical Interview Schedule (CIS-R). The International Classification of Diseases-10: Primary care version (ICD-10 PHC) criteria were used to diagnose CMD. Various thresholds of the GHQ-12 were compared against the standards of the ICD-10 PHC. A receiver operator characteristic curve was drawn to obtain the best threshold value for screening. Principal Component Analysis was done to identify latent variables. The Cronbach's alpha and the split half reliability were also calculated. One hundred and eleven (33%) subjects of the 327 patients interviewed satisfied ICD-10 PHC criteria for CMD. The optimal threshold for the GHQ-12 was 2/3. This threshold had a sensitivity 87.4% and a specificity of 79.2%. Three factors were extracted with eigen values of 5.0 (depression-anxiety), 1.7 (social performance) and 1.1 (self-esteem) which explained 42.0%, 13.9% and 9.2% of the variance. The Cronbach's alpha was 0.86 while the split half-reliability was 0.83. The sensitivity and specificity of the Tamil version of the GHQ-12 is high. The factor structure is similar to that reported in other populations. The instrument can be employed as a screening instrument in this population.