Association of heartbeat complexity with survival in advanced non-small cell lung cancer patients

BackgroundPrevious studies have shown that the predictive value of traditional linear (time domain and frequency domain) heart rate variability (HRV) for the survival of patients with advanced non-small cell lung cancer (NSCLC) is controversial. Nonlinear methods, based on the concept of complexity, have been used to evaluate HRV, providing a new means to reveal the physiological and pathological changes in HRV. This study aimed to assess the association between heartbeat complexity and overall survival in patients with advanced NSCLC.MethodsThis study included 78 patients with advanced NSCLC (mean age: 62.0 ± 9.3 years). A 5-min resting electrocardiogram of advanced NSCLC patients was collected to analyze the following HRV parameters: time domain indicators, i.e., standard deviation of the normal-normal intervals (SDNN) and root mean square of successive interval differences (RMSSD); frequency domain indicators, i.e., total power (TP), low frequency power (LF), high frequency power (HF), and the ratio of LF to HF (LF/HF); nonlinear HRV indicators characterizing heartbeat complexity, i.e., approximate entropy (ApEn), sample entropy (SampEn), and recurrence quantification analysis (RQA) indexes: mean diagonal line length (Lmean), maximal diagonal line length (Lmax), recurrence rate (REC), determinism (DET), and shannon entropy (ShanEn).ResultsUnivariate analysis revealed that the linear frequency domain parameter HF and nonlinear RQA parameters Lmax, REC, and DET were significantly correlated with the survival of advanced NSCLC patients (all p < 0.05). After adjusting for confounders in the multivariate analysis, HF, REC, and DET were found to be independent prognostic factors for the survival of patients with advanced NSCLC (all p < 0.05).ConclusionThere was an independent association between heartbeat complexity and survival in advanced NSCLC patients. The nonlinear analysis method based on RQA may provide valuable additional information for the prognostic stratification of patients with advanced NSCLC and may supplement the traditional time domain and frequency domain analysis methods

Simple Tests for Assessing Kidney and Cardiovascular Function in Chromic Kidney Disease Patients (Stages 2, 3 and 4)

Reliable measurement of glomerular filtration rate (GFR) is an important aspect of clinical decision making and forms the basis of classification for kidney function. Moreover the interpretation of risk factors for progression of CKD linked to cardiovascular disease (CVD) remains difficult, particularly in older subjects. To address this GFR and the cardiovascular parameters arterial stiffness, heart rate variability (HRV) and natriuretic peptides (NT- proBNP and NT-proCNP) were measured in a cohort of CKD patients of stages 2,3 and 4. The primary aim however of the thesis was to measure the Kidney Functional Reserve (KFR) of CKD3 and CKD4 patients as it has been thought of as analogous to cardiac functional reserve. CysC, creatinine clearance (CrCl) and with simultaneous radionuclide 99technetium diethylenetriaminepentaacetatic acid (Tc-99m) measured GFR (mGFR) of KFR in 19 CKD Stage 3 and 21 CKD Stage 4 patients yielded good agreement. KFR was not correlated with baseline kidney function. Eight CKD Stage 3 (42%) and 11 CKD Stage 4 (52%) subjects reached their lowest serum CysC concentration 4 hours after OPL. CysC KFR and baseline serum creatinine (sCr) predicted Major Adverse Kidney Event, death or dialysis (MAKE-T) and MAKE-F (fast progression with GFR decrease > 5ml/min/year) with a respective area under the curve (AUC) of 0.73 (95% confidence interval [CI] 0.48 – 0.890) and 0.71 (95% CI: 0.51–0.84). Including CysC KFR, age, baseline sCr and nadir CysC predicted a decrease in sCr-estimated GFR >1.2 ml/min/year (MAKE-S) with an AUC of 0.89. In the latter case the inclusion of cardiovascular variables; “Recovery” (1-4 minutes post exercise) RMSSD, urinary and serum NT-proCNP concentration and whether CysC GFR reserve was early or late in nadir improved the AUC to 1.00 (AICc =15.41). In conclusion serial CysC may facilitate monitoring of KFR in clinical practice along with the use of a portable exercise stress test to increase c-f-PWV (carotid-femoral Pulse Wave Velocity) and identify CKD patients with serious/subliminal vascular stiffening. Future research may confirm this studies other preliminary finding that urinary NT-proCNP concentration may relate to renal haemodynamic function in CKD stages, as this correlated with stimulated mGFR (R2 = 0.41). In short this thesis has furthered the premise that the heart and kidney are interlinked via cardiovascular physiology which likely can be used to predict CKD progression