Improvement in quality of life and angina pectoris: 1-year follow-up of patients with refractory angina pectoris and spinal cord stimulation

Aims

Spinal cord stimulation (SCS) is a treatment for patients with refractory angina pectoris (RAP) who remain symptomatic despite optimal medical therapy and without revascularisation options. Previous studies have shown that SCS improves the quality of life in this patient group and reduces the severity of the angina pectoris. The aim of this prospective, single-arm observational study is to show this effect in a single-centre cohort using a multidisciplinary team approach to the selection process, with a follow-up period of 1 year.

Methods and results

Between July 2010 and March 2017, 87 patients with RAP referred to our centre received SCS. The Seattle Angina Questionnaire (SAQ) and RAND 36-Item Health Survey (RAND-36) were completed at baseline, prior to implantation, and 1 year post-implantation. After 1 year of follow-up there was a statistically significant decrease in the frequency of angina pectoris attacks from more than 4 times a day to 1–2 times a week (p < 0.001). The SAQ showed statistically significant improvement in four of the five dimensions: physical limitation (p < 0.001), angina frequency (p < 0.001), angina stability (p < 0.001) and quality of life (p < 0.001). The RAND-36 showed statistically significant improvement in all nine dimensions: physical functioning (p = 0.001), role/physical (p < 0.001), social functioning (p = 0.03), role/emotional (p < 0.05), bodily pain (p < 0.001), general health (p < 0.001), vitality (p < 0.001), mental health (p = 0.02) and health change (p < 0.001).

Conclusion

This study showed a significant improvement in quality of life and reduction of angina pectoris severity after 1 year of follow-up in patients treated with SCS for RAP.

     

Simultaneous estimation of nicotine and cotinine levels in biological fluids using high-resolution capillary-column gas chromatography combined with solid phase extraction work-up

A rapid and sensitive capillary gas-chromatographic method with nitrogen-sensitive detection is reported for the simultaneous analysis of nicotine and cotinine levels occurring in the plasma, saliva, and urine of regular tobacco smokers. The proposed assay has a linear output, has satisfactory accuracy over the range of concentrations of both amines encountered in active smokers, and has also been successful in the analysis of the urine samples of passive smokers. Its lower limit of sensitivity is 0.2 ng of nicotine and 0.5 ng of cotinine per ml of plasma or saliva or per 100 l of urine.The beneficial characteristics of the presented method were achieved by the combination of solid phase extraction of 0.1–1.0 ml of fluid specimens, capillary column gas chromatography with splitless injection and nitrogen sensitive detection, and the use of separate, structurally analogous compounds as internal standards for nicotine. The suitability of the assay is shown by plasma concentration-time curves of nicotine and cotinine in a steady smoker during a 24 hours period.     

Rapid and sensitive gas-chromatographic determination of caffeine in blood plasma,saliva, and xanthine beverages

A gas chromatographic procedure is reported for the determination of caffeine in plasma, saliva, and xanthine beverages. Using a 75 cm column packed with OV-17, nitrogen-sensitive detection, and 1 ml samples, a suitable limit of analysis (coefficient of variation (CV)=10.2%) of 50 ng/ml was obtained in plasma. Within-day CVs at caffeine concentrations of 0.1–0.5–2.0–7.5–15.0 g/ml in plasma were 7.7–5.6–4.8–3.8–3.4%, respectively. The limit of detection, defined as the injected quantity of caffeine giving rise to a signal to noise ratio of 2, is 40 pg, corresponding to a plasma concentration of 1 ng/ml.The procedure involves addition of the internal standard 7-pentyl theophylline and alkaline extraction of the sample with dichloromethane. The method described rivals any gaschromatographic assay published so far in rapidness and accuracy.Plasma and saliva caffeine concentrations were determined in a healthy male volunteer after swallowing 400 ml of coffee. The calculated pharmacokinetic parameters, assuming complete absorption of caffeine from the G.I. tract, agree well with previously published values.     

Coronary physiology before and after chronic total occlusion treatment: what does it tell us?

Studies performed in the last two decades demonstrate that after successful percutaneous coronary intervention (PCI) of a chronically occluded coronary artery, the physiology of the chronic total occlusion (CTO) vessel and dependent microvasculature does not normalise immediately but improves significantly over time. Generally, there is an increase in fractional flow reserve (FFR) in the CTO artery, a decrease in collateral blood supply and an increase in FFR in the donor artery accompanied by an increase in blood flow and decrease in microvascular resistance in the myocardium supplied by the CTO vessel. Analogous to these physiological changes, positive remodelling of the distal CTO artery also occurs over time, and intravascular imaging can be helpful for analysing distal vessel parameters. Follow-up coronary angiography with physiological measurements after several weeks to months can be helpful and informative in a subset of patients in order to decide upon the necessity for treatment of residual coronary artery stenosis in the vessel distal to the CTO or in the contralateral donor artery, as well as in deciding whether stent optimisation is indicated. We suggest that such physiological guidance of CTO procedures avoids unnecessary overtreatment during the initial procedure, guides interventions at follow-up, and improves our understanding of what PCI in CTO means.