Aim. To study the pathogenetic and clinical features of nephrolithiasis in patients with concomitant chronic cardiovascular diseases (CVD), particularly the chemical composition of renal stones, the frequency of relapses, as well as the daily dynamics of the urine specific gravity and acidity level as the main factors of stone formation.
Materials and methods. A total of 270 patients were treated in the Department of the urology No. 1 of the "Main Military Clinical Hospital named after N. N. Burdenko" of the Ministry of Defense of the Russian Federation during the period from 2008 to 2018. The main group included 184 patients suffering from nephrolithiasis, of which 72 had hypertension in combination with coronary heart disease, and in other 112 patients chronic heart failure (CHF of stage I, IIA and IIB in 55, 37 and 20 patients, respectively) was previously diagnosed. Data on the CVD were obtained from medical records; if necessary, patients were referred to an internist and/or cardiologist. The CHF was staged in accordance with the Strazhesco–Vasilenko (1935) classification. In the control group there were 86 patients with urolithiasis without any cardiovascular disorders. A retrospective analysis of the stone composition was performed using a NICOLET iS10 spectral analyzer. The urine specific gravity and acidity (pH) was determined using a semi-automatic analyzer CLINITEK Status Plus three times a day (both during hospital stay and 3 months after discharge). Statistical analysis was done using the SPSS program v.19. The absolute values (M±m) were calculated, as well as Min, ME, Mo, Max. Relative values, including Fischer criterion, were evaluated, taking into account the Bonferroni correction. Differences were significant if p-value was < 0.05.
Results. There was no difference between groups in age (32; 64; 83). In both groups men were predominated (~ 75-78%). According to chemical analysis, stone composition in the control group was as following: oxalates (76.6%), uric acid (9.3%), phosphates (8.1%); mixed stones (6.7%). Independent of stage of CHF, respective figures were 51.4, 23.6, 8.3 and 16%, respectively. The follow-up of patients for 5 years showed that patients were admitted to the urological hospital with a stone recurrence on average 1.8 times, compared to 3 and 3.8 times with concomitant CVD and CHF, respectively. The most concentrated (specific gravity of 1035) and the most acidic (pH =5.5–5) urine in patients with CHF was found in the evening.
Conclusion. Chronic CVD has a significant impact on the clinical manifestations of urinary stone disease. The most pronounced changes are associated with CHF. Features of nephrolithiasis in patients with a CVD include the predominance of uric acid and urate stones, more frequent recurrences, shift in the peak of acidity and urine specific gravity from morning to evening hours.

Keywords: recurrent urolithiasis, urolithiasis, cardiovascular diseases, chronic heart failure