Reduced Cardiovascular Reserve in Chronic Kidney Failure: A Matched Cohort Study

Background: Patients with chronic kidney failure (CKF) experience impaired functional cardiovascular reserve with reduced oxygen consumption at peak exercise (Vo2peak). No studies have examined whether this is related to impaired cardiovascular compliance as a consequence of loss of adaptive structural alterations, resulting from chronic uremia or hypertension. Study Design: Prospective matched-cohort study. Setting & Participants: We assessed CKF in parallel with patients with essential hypertension but without cardiovascular disease. Patients with CKF were either scheduled for kidney transplantation or transplant waitlisted. 80 patients with CKF and 80 with essential hypertension matched in age, sex, and body mass index were evaluated. 61 patients with CKF (76.3%) were dialysis dependent. Predictor: CKF versus essential hypertension without cardiovascular disease. Measurements & Outcomes: Vo2peak was measured during maximal exercise testing. 2-dimensional echocardiography and arterial applanation tonometry were performed prior to exercise testing. To evaluate for the difference in Vo2peak between study groups, statistically significant predictors of Vo2peak in multiple regression models were additionally assessed by fitting models comprising the interaction term of patient group with the predictor variable of interest. Results: Vo2peak was significantly lower in patients with CKF than those with essential hypertension (18.8 vs 24.5 mL/min·kg; P < 0.001). Independent predictors of Vo2peak for CKF included left ventricular (LV) filling pressure (E/mean e′; unstandardized regression coefficient: change in Vo2peak [in mL/min·kg] per 1-unit change of variable = −5.1) and pulse wave velocity (−4.0); in essential hypertension, these were LV mass index (0.2), LV end-diastolic volume index (0.4), peak heart rate (0.2), and pulse wave velocity (−8.8). The interaction effect of Vo2peak between patient groups with LV mass index (P < 0.001), LV end-diastolic volume index (P < 0.001), and peak heart rate (P < 0.01) were significantly stronger in the hypertension group, whereby higher values led to greater Vo2peak. Limitations: Skeletal muscle strength was not assessed. Conclusion: This study suggests that maladaptive LV changes, as well as blunted chronotropic response, are important mechanistic factors resulting in reduced cardiovascular reserve in patients with CKF, beyond predominantly vascular changes associated with hypertension

Cardiovascular Functional Reserve Before and After Kidney Transplant.

Importance: Restitution of kidney function by transplant confers a survival benefit in patients with end-stage renal disease. Investigations of mechanisms involved in improved cardiovascular survival have relied heavily on static measures from echocardiography or cardiac magnetic resonance imaging and have provided conflicting results to date. Objectives: To evaluate cardiovascular functional reserve in patients with end-stage renal disease before and after kidney transplant and to assess functional and morphologic alterations of structural-functional dynamics in this population. Design, Setting, and Participants: This prospective, nonrandomized, single-center, 3-arm, controlled cohort study, the Cardiopulmonary Exercise Testing in Renal Failure and After Kidney Transplantation (CAPER) study, included patients with stage 5 chronic kidney disease (CKD) who underwent kidney transplant (KTR group), patients with stage 5 CKD who were wait-listed and had not undergone transplant (NTWC group), and patients with hypertension only (HTC group) seen at a single center from April 1, 2010, to January 1, 2013. Patients were followed up longitudinally for up to 1 year after kidney transplant. Clinical data collection was completed February 2014. Data analysis was performed from June 1, 2014, to March 5, 2015. Further analysis on baseline and prospective data was performed from June 1, 2017, to July 31, 2019. Main Outcomes and Measures: Cardiovascular functional reserve was objectively quantified using state-of-the-art cardiopulmonary exercise testing in parallel with transthoracic echocardiography. Results: Of the 253 study participants (mean [SD] age, 48.5 [12.7] years; 141 [55.7%] male), 81 were in the KTR group, 85 in the NTWC group, and 87 in the HTC group. At baseline, mean (SD) maximum oxygen consumption (V̇O2max) was significantly lower in the CKD groups (KTR, 20.7 [5.8] mL · min-1 · kg-1; NTWC, 18.9 [4.7] mL · min-1 · kg-1) compared with the HTC group (24.9 [7.1] mL · min-1 · kg-1) (P < .001). Mean (SD) cardiac left ventricular mass index was higher in patients with CKD (KTR group, 104.9 [36.1] g/m2; NTWC group, 113.8 [37.7] g/m2) compared with the HTC group (87.8 [16.9] g/m2), (P < .001). Mean (SD) left ventricular ejection fraction was significantly lower in the patients with CKD (KTR group, 60.1% [8.6%]; NTWC group, 61.4% [8.9%]) compared with the HTC group (66.1% [5.9%]) (P < .001). Kidney transplant was associated with a significant improvement in V̇O2max in the KTR group at 12 months (22.5 [6.3] mL · min-1 · kg-1; P < .001), but the value did not reach the V̇O2max in the HTC group (26.0 [7.1] mL · min-1 · kg-1) at 12 months. V̇O2max decreased in the NTWC group at 12 months compared with baseline (17.7 [4.1] mL · min-1 · kg-1, P < .001). Compared with the KTR group (63.2% [6.8%], P = .02) or the NTWC group (59.3% [7.6%], P = .003) at baseline, transplant was significantly associated with improved left ventricular ejection fraction at 12 months but not with left ventricular mass index. Conclusions and Relevance: The findings suggest that kidney transplant is associated with improved cardiovascular functional reserve after 1 year. In addition, cardiopulmonary exercise testing was sensitive enough to detect a decline in cardiovascular functional reserve in wait-listed patients with CKD. Improved V̇O2max may in part be independent from structural alterations of the heart and depend more on ultrastructural changes after reversal of uremia

A survey of physician practices in managing people with dementia in Hong Kong

2015-2016 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Superior blood pressure control among hypertensive patients attending specialist clinics in Malaysia

Background The prevalence of hypertension in Malaysia is alarmingly high. The National Survey in 2006 showed 43% of people above 30 years old have hypertension and only 8% reached target blood pressure (BP) of <140/90 mmHg. Among treated patients, only 26% reached target BP. We aimed to evaluate BP control among hypertensives attending Specialist institutions in Malaysia. Methods This prospective study aimed at determining BP control among hypertensive patients attending three specialist institutions in Malaysia located in Kuala Lumpur (KL), Kuantan and Kota Bharu( KB). 950 consecutive patients with known hypertension for at least 6 months were recruited between January 2007 and July 2008. Patients’ demography, BP, cardiovascular (CV) risk factors and medications were obtained. Results A total of 950 patients were recruited. There were more males (n=548, 57.7%) compared to females (n=402, 42.3%). The mean age was 60.9 ± 10.8. The mean Systolic BP (SBP) and diastolic BP (DBP) was 138.8 ± 20.3 mm Hg and 79.6 ±11.4 mmHg respectively. 49.4% of all patients had BP controlled (< 140/90 mmHg) with mean SBP and DBP of 123.2 ± 9.4 mm Hg and 74.2 ± 8.3 mmHg respectively. Males had better SBP control compared to female (SBP 135.9 ± 18.7 vs 142.8 ± 21.7 mmHg, p < 0.001); DBP 77.1 ± 13.7 vs 78.0 + 12.1 mmHg, p = 0.58). Majority of patients were on 2 or 3 antihypertensives (67.6%). BP control among the three centres were consistently good compared to the national figure of 26% (45.1% in KL, 47.1% in Kuantan and 56.3% in KB). Prevalence of CV risk factors was as follows: 54.6% had ischaemic heart disease (IHD), 24.2% underwent coronary revascularization, 50.1% diabetic, 68.7% hyperlipidaemic, 21% smokers and 28% had chronic kidney disease (CKD). Conclusion Tertiary institutions demonstrated much better control of hypertension among their hypertensive patients. Compared to that of national figure, there is a near two-fold difference in the ratio of well controlled BP. Majority of these patients fall into high risk group for CV events, thereby necessitating intensive BP management. This reassuring result suggested the much anticipate

The effect of biliopancreatic diversion surgery on renal function--a retrospective study.

BACKGROUND The prevalences of obesity and chronic kidney disease (CKD) have increased simultaneously. Should a pathophysiological relationship exist between the two conditions, bariatric surgery and associated weight loss could be an important intervention in extremely obese individuals to slow the progression of CKD. METHODS We conducted a retrospective analysis of 25 patients who had undergone biliopancreatic diversion (BPD) surgery for extreme obesity (body mass index >40 kg/m(2)), with mean follow-up of 4 years. We assessed pre- and post-surgery renal function, body weight and blood pressure (BP) obtained from electronic hospital and primary care records. RESULTS There was a significant reduction in mean body weight at 4 years by 50.3 kg (SD = 20.65). The creatinine and estimated glomerular filtration rate (eGFR) also improved significantly: serum creatinine reduced by 16.2 μmol/l (SD = 19.57) while the eGFR improved by 10.6 ml/min/m(2) (SD = 15.45). The greatest improvement in eGFR was in the group (n = 7) with eGFR ≤60 ml/min/m(2). A subset of patients (n = 11) had evaluable BP readings and had a reduction in BP of 17/10 mmHg (SD = 33/12). CONCLUSIONS This retrospective study demonstrates a clinically significant improvement in renal function following BPD. Several mechanisms including weight loss could account for the positive impact on renal function. The physiology underlying this improvement requires further study