Chest pain after coronary interventional procedures. Incidence and pathophysiology

Validation of the Fitbit Flex in an Acute Post-Cardiac Surgery Patient Population

Purpose: This study examined the validity of the Fitbit Flex activity monitor for step count and distance walked among post-cardiac surgery patients. Method: Participants (n=20) from a major urban cardiac surgery centre were recruited 1-2 days before hospital discharge. The Fitbit Flex step count and distance walked outputs and video recording of each participant performing the 6-minute walk test were collected. Fitbit Flex output was compared with criterion measures of manual step count obtained from the video recording and manual measurement of distance walked. Statistical analysis compared the output and criterion measures using paired sample t-tests, Pearson correlation coefficients, Lin's concordance correlations, and Bland-Altman plots. Sub-analysis compared slower walking (<0.8 m/s; n=11) and faster walking (≥0.8 m/s; n=8) group speeds (1 participant was excluded from analysis). Results: Steps counted and distance walked were significantly different between the Fitbit Flex outputs and criterion measures (p<0.05). The Fitbit Flex steps counted and distance walked showed moderate association with manual measure steps counted (r=0.67) and distance walked (r=0.45). Lin's concordance coefficients revealed a lack of agreement between the Fitbit Flex and the criterion measurement of both steps counted (concordance correlation coefficient [CCC]=0.43) and distance walked (CCC=0.36). The percentage of relative error was -18.6 (SD 22.7) for steps counted and 25.4 (SD 45.8) for distance walked. Conclusions: The Fitbit Flex activity monitor was not a valid measure of step count and distance walked in this sample of post-cardiac surgery patients. The lack of agreement between outputs and criterion measures suggests the Fitbit Flex alone would not be an acceptable clinical outcome measure for monitoring walking progression in the early postoperative period.

Patient care before and after percutaneous coronary artery interventions

Care of the patient before and after percutaneous coronary interventions has changed largely because of the increased use of stents. Important patient management issues include the evaluation of chest pain after the procedure, recognition of acute vessel closure during the periprocedural period, management of the vascular access site, and prevention of contrast-induced renal dysfunction. Risk factor modification and drug therapies are important interventions for the secondary prevention of coronary events. Functional testing has a meaningful role in the evaluation of some patients after coronary intervention. It is important for the specialist in internal medicine to have a firm working knowledge of the various aspects of patient care before and after these procedures because their role in the management of these patients is increasing.

A descriptive study of early nonspecific chest pain after PTCA: important area for the acute health care personnel

BACKGROUND

Many patients report chest pain of varying intensity at various locations during the first hours after percutaneous transluminal coronary angioplasty (PTCA).

OBJECTIVES

The aim of the study was to increase knowledge regarding differentiating between harmless chest pain versus ischemic chest pain, focusing on patients description of their pain.

METHODS

A total of 192 patients after elective PTCA were interviewed twice. In addition patients experiencing chest pain within 6 hours after the procedure completed the McGill Pain Questionnaire (MPQ).

RESULTS

Nonspecific chest pain occurred in 34 patients (18%) and ischemic chest pain in 6 (3%), whereas 152 (79%) did not report early chest pain after PTCA. The nonspecific pain group reported statistically significant less pain intensity (VAS P =.001), used fewer (P =.006) and qualitatively weaker (P =.008) words compared to the ischemic pain group. No predisposing factors that could predict chest pain were identified.

CONCLUSIONS

Discriminators appear to be the pain intensity and the word descriptors. MPQ combined with a VAS could be valuable clinical tools with regard to patients' description of pain.

Arterial stenting and overdilation: does it change wall mechanics in small-caliber arteries?

PURPOSE

To evaluate changes in arterial wall mechanics induced by stent overdilation in the rabbit aorta.

METHODS

Twenty New Zealand white rabbits had initial stent deployment (3-mm x 8-mm Multilink) at 10% overdilation. Group A (n=11) had no subsequent balloon expansion of the stent and Group B (n=9) had 30% overdilation of the stent. A noninvasive B-mode ultrasound examination coupled with image processing allowed the measurement of systolic and diastolic diameter and the calculation of diameter compliance (Cd) and distensibility coefficient (DC) as indexes of arterial wall biomechanics. Measurements were performed before stenting in the infrarenal aorta, after initial stenting, and after stent overdilation at 3 locations: upstream, at the stent level, and downstream from the stent.

RESULTS

Cd was significantly lower in the stented aorta after initial stenting (p<0.0001) and after stent overdilation (p<0.0001) than before stenting. At the stent level, Cd and DC were significantly lower than downstream (p<0.0001) or upstream (p<0.0001) from the stent after initial stenting, as well as after stent overdilation. Downstream from the stent, Cd and DC were significantly lower after stent overdilation than before stenting (p<0.05).

CONCLUSIONS

Endovascular stenting of the rabbit aorta produces a significant decrease in arterial wall compliance and distensibility. Stent overdilation is responsible for a slight additional decrease of compliance downstream from the stent.