Incidence of Kidney Stones in the United States: The Continuous National Health and Nutrition Examination Survey.

PURPOSE: The incidence of kidney stones in the United States is currently unknown. Here, we assessed the incidence of kidney stones using recent, nationally representative data. MATERIALS AND METHODS: We used the National Health and Nutrition Examination Survey (NHANES) from 2015 to 2018. During this time participants were asked, "Have you ever had a kidney stone?" and "In the past 12 months, have you passed a kidney stone?" Demographics analyzed include age, race, gender, body mass index, history of smoking, diabetes, hypertension, hypercholesterolemia and gout. Multivariable models were used to assess the independent impact of subject characteristics on kidney stone prevalence and incidence. RESULTS: Data were available on 10,521 participants older than age 20. The prevalence of kidney stones was 11.0% (95% CI 10.1-12.0). The 12-month incidence of kidney stones was 2.1% (95% CI 1.5-2.7), or 2,054 stones per 100,000 adults. We identified significant relationships between stone incidence and subject age, body mass index, race and history of hypertension. CONCLUSIONS: Here we find a substantially higher 12-month incidence of kidney stones than previous reports. We also validate known risk factors for stone prevalence as associated with incidence. The remarkable incidence and prevalence of stones is concerning and has implications for disease prevention and allocation of medical resources.

Variations in Thebesian valve anatomy and coronary sinus ostium: implications for invasive electrophysiology procedures.

AIMS: The coronary sinus (CS) is a commonly cannulated structure in patients undergoing electrophysiology studies, catheter ablation of arrhythmias, implantation of resynchronization therapy devices and, more recently, percutaneous mitral valve repair. The advent of these procedures has led to a renewed interest in the anatomy of the coronary venous system including its various components. To improve our understanding of this structure, we studied the anatomy of the human CS, including the valve that guards its ostium, the Thebesian valve. METHODS AND RESULTS: In 75 randomly selected autopsied human hearts, we measured the transverse and craniocaudal dimensions of the CS ostium and characterized the shape, composition, per cent coverage, and attachment points of the Thebesian valve when present. Of the 75 hearts examined, 54 had organic heart disease including atherosclerotic coronary artery disease, left ventricular hypertrophy, dilated cardiomyopathy, rheumatic heart disease, infective endocarditis, and non-rheumatic valvular heart disease. A wide variety of Thebesian valve morphologies were seen, ranging from the absence of any valve to those where the valve was completely occluding the CS ostium. A Thebesian valve was present in the majority of the hearts examined (55/75 hearts-73%). The average transverse dimension of the CS ostium in hearts with Thebesian valves (7.3+/-2.8 mm) was significantly shorter than those without Thebesian valves (9.4+/-2.9 mm, P=0.005). Similarly, the average craniocaudal dimension of the CS ostium in hearts with Thebesian valves (7.9+/-2.7 mm) was also significantly shorter than those without Thebesian valves (9.3+/-2.9 mm, P=0.045). CONCLUSION: Our study shows that some form of Thebesian valve is present in the majority of hearts (>70%). Of these, a significant minority (16%) had a valve morphology (covering >75% of the ostium, a fibrous, fibromuscular, or muscular composition, and devoid of fenestrations) that makes them a 'potentially complicating' structure interfering with the cannulation of the CS.

Cardiac device testing enhanced by simultaneous imaging modalities: the Visible Heart, fluoroscopy and echocardiography.

The evaluation of implantable cardiac devices requires innovative and critical testing in all phases of the design process. The recent development of an in vitro isolated heart model, the Visible Heart, allows for novel examination of device-tissue interactions to evaluate device placement and performance within a functioning heart. This model provides product designers with a rapid method to critically assess prototypes, thus expediting design decisions. The future of cardiac devices will include beating heart procedures (e.g., transcatheter-delivered valves), and such implantations will probably utilize simultaneous multiple imaging modalities. These imaging modes allow for verification of proper device positioning, refinement of device/deployment procedures, and eventual evaluation of resultant cardiac function within experimental and clinical settings.

The clinical anatomy and pathology of the human atrioventricular valves: implications for repair or replacement.

A critical understanding of cardiac anatomy is essential for design engineers and clinicians with the intent of developing and/or employing improved or novel technologies or therapies for treating an impaired atrioventricular valve. Likewise, such knowledge is required for directing translational research, including initiating preclinical research, assessing the feasibility of clinical trials, and performing first-in-man procedures. There are two atrioventricular valves in the human heart, namely the tricuspid and mitral valves. Both are complex structures whose normal anatomies can vary greatly amongst individuals, and also become modified by disease processes. In this review, we discuss the anatomy, pathology, and issues related to surgical and transcatheter repair of the atrioventricular valves in a translational manner. This article is part of a JCTR special issue on Cardiac Anatomy.

The clinical anatomy and pathology of the human arterial valves: implications for repair or replacement.

A thorough understanding of valvar anatomy is essential for design engineers and clinicians in the development and/or employment of improved technologies or therapies for treating valvar pathologies. There are two arterial valves in the human heart--pulmonary and aortic valves. Both are complex structures whose normal anatomical components can vary greatly between individuals. We discuss the anatomy, pathology, and challenges relating to transcatheter and surgical repair/replacement of the arterial valves in a translational manner. The high prevalence of aortic valvar pathologies in the burgeoning elderly population, coupled with poor clinical outcomes for patients who go untreated, has resulted in prolific spending in the research and development of more effective and less traumatic therapies. The accelerated development of therapies for treating arterial valves has been guided by anatomical information gathered from high-resolution imaging technologies, which have focused attention on the need for complete understanding of arterial valvar clinical anatomies. This article is part of a JCTR special issue on Cardiac Anatomy.

Accuracy of aortic annular measurements obtained from three-dimensional echocardiography, CT and MRI: human in vitro and in vivo studies.

OBJECTIVES: To determine the accuracy of calcium-containing rings measurements imaged by three-dimensional echocardiography (3DE), multi-slice CT (MSCT) and cardiac magnetic resonance (CMR) under ideal conditions against the true ring dimensions. To compare the accuracy of aortic annulus (AoA) measurements in ex vivo human hearts using 3DE, MSCT and CMR. To determine the accuracy of AoA measurements in an in vivo human model. DESIGN: 3DE, MSCT and CMR imaging were performed on 30 calcium-containing rings and 28 explanted human hearts. Additionally, 15 human subjects with clinical indication for MSCT underwent 3DE. Two experts in each modality measured the images. MAIN OUTCOME MEASURES: Bias and intraclass correlation coefficient for accuracy of imaging measurements when compared with actual ring dimensions. Bias, intraclass correlation coefficient and variability were obtained: (1) when comparing explanted human heart AoA measurements from the two remaining imaging modalities with the most accurate one as determined from the ring measurements and (2) in in vivo human AoA measurements. Analysis was repeated on explanted heart subgroups divided by aortic valve Agatston score. RESULTS: Against the known ring dimensions, CMR had the highest accuracy and the lowest variability. MSCT measurements had high accuracy but wider variability and 3DE had the lowest accuracy with the largest variability. When 3DE and MSCT were compared with CMR, 3DE underestimated and MSCT overestimated AoA dimensions, but inter-measurement variability of 3DE and MSCT were similar. When divided by Agatston score, both 3DE and MSCT measurements were larger and showed greater variability with increasing calcium burden. The in vivo study showed that the correlation between 3DE and MSCT measurements was high; however, 3DE measurements were smaller than those measured with MSCT. CONCLUSIONS: In the in vitro model, CMR measurements were the most accurate for assessing the actual dimensions suggesting that further investigations on its role in AoA measurement in TAVR are needed. However from the in vivo model, MSCT and 3DE are reasonable alternatives with the understanding that they can slightly overestimate and underestimate annular dimensions, respectively.

Microanatomy of human left ventricular coronary veins.

We describe analyses of the microanatomy of major left ventricular veins, including their relationship to the myocardium. Immediately following fixation of six fresh human hearts, anterior interventricular veins (AIV), left marginal veins (LMV), posterior veins of the left ventricle (PVLV), and posterior interventricular veins (PIV) were sectioned in approximately 5 mm intervals perpendicular to the veins' length from base to apex. Slides were prepared, digitized, and analyzed; measurements were made of each vein's wall thickness, circumference, distance between vein wall and myocardium, and distance between vein wall and closest artery. For analyses, based on the length of each vein, slides were grouped into three regions: basal (top third), mid (middle third), and apical (bottom third). Vein wall thicknesses and circumferences were significantly smaller (P < 0.05) in apical than basal regions in all veins. Vein wall thicknesses were significantly larger in the AIV and PIV than in the LMV and PVLV (P < 0.05). The AIV was significantly farther away (1.81-2.99 mm) from the myocardium than the other three veins (P < 0.05). Left ventricular venous microanatomy was quantified and analyzed. Variation in venous microanatomy, including distance between vein walls and excitable myocardium, could impact therapies involving the coronary venous system. Anat Rec, 2009. (c) 2008 Wiley-Liss, Inc.

Mitral leaflet anatomy revisited.

OBJECTIVE: The aims of this work were to employ functional imaging capabilities of the Visible Heart laboratory and endoscopic visualization of mitral valves in perfusion-fixed specimens to better characterize variability in mitral valve leaflet anatomy and to provide a method to classify mitral leaflets that varies from the current nomenclature. METHODS: We gathered functional endoscopic video footage (11 isolated reanimated human hearts) and static endoscopic anatomical images (38 perfusion-fixed specimens) of mitral leaflets. Commissure and cleft locations were charted using Carpentier's accepted description. RESULTS: All hearts had 2 commissures separating anterior and posterior leaflets. "Standard" clefts separating P1/P2 were found in 66% of hearts (n = 25), and standard clefts separating P2/P3 were present in 71% of hearts (n = 27). "Deviant" clefts occurred in each region of the anterior leaflet (A1, A2, A3), and their relative occurrences were 5%, 8%, and 13% (n = 2, 3, 5), respectively. Deviant clefts were found in posterior leaflets: 13.2% in P1 (n = 5), 32% in P2 (n = 12), and 21% in P3 (n = 8). CONCLUSIONS: Humans elicit complex and highly variable mitral valve anatomy. We suggest a complementary, yet simple nomenclature to address variation in mitral valve anatomy by describing clefts as either standard or deviant and locating regions in which they occur (A1 to A3 or P1 to P3).

Excitation of the intrinsic conduction system through his and interventricular septal pacing.

BACKGROUND: Direct His bundle pacing results in rapid synchronous ventricular activation. However, clinical experiences with such pacing have been associated with long procedure times and compromised pacing and sensing performance. METHODS: We evaluated myocardial activation sequences (AS) for pacing of the His bundle and peri-His region and assessed acute pacing performance using custom-designed plunge electrodes. Unipolar pacing was performed in isolated swine hearts (n = 10) using four quadripolar stimulation/sensing electrodes implanted into the interventricular septum and equally spaced between the membranous septum and the coronary sinus ostium (zones 1-4, respectively; electrode depth (ED) 1 = most distal, ED 4 = most proximal). Optimal pacing sites were defined as: pacing thresholds < or = 1.5 V, a P-R ratio of < or = 0.5, and > or = 50% occurrence of an intrinsic midseptal left ventricular (LV) endocardial electrical breakout (BO) and activation pattern. RESULTS: Pacing thresholds improved with greater depth of electrode location within the septum (ED 1: 1.51 +/- 0.8 V vs ED 4: 5.2 +/- 3.8 V, P < 0.001), as did the P-R ratio (0.34 +/- 0.6 vs 0.78 +/- 1.0, P < 0.05). His potentials were only observed in zone 1 and 2 electrodes (0.12 and 0.02 mV, respectively). Only electrodes in zones 1 and 2 produced LV endocardial electrical BOs in the midseptal region that demonstrated an intrinsic-like endocardial AS. Depth 1 and 2 electrodes (11.75 and 8.75 mm, respectively) in zone 1 satisfied all three optimal pacing site requirements. CONCLUSIONS: This study has shown that LV activation patterns similar to sinus rhythm may be achieved without direct activation of the His bundle, while maintaining acceptable pacing and sensing performance. These data indicate that pacing systems designed to stimulate the tissues below the point at which the His bundle penetrates the central fibrous body may provide improved system efficiency and LV performance in comparison to both direct His bundle pacing and traditional pacing sites.

In vitro studies of human hearts.

BACKGROUND: Isolated mammalian hearts have been used in numerous studies that have led to many important discoveries in cardiac physiology, pharmacology, and surgery. Multiple methods of perfusion have been described including retrograde and/or antegrade flows and crystalloid or blood perfusates. Furthermore, multiple species have been utilized for such studies including the following: rat, rabbit, guinea pig, canine, and swine. The objective of this study was to describe a unique isolated heart preparation, utilizing human hearts not viable for transplant, which allows for physiologic perfusion and endocardial imaging. METHODS: Utilizing standard cardiac transplantation procedures, 12 human hearts deemed not viable for transplant were explanted to an isolated heart apparatus. A clear, modified Krebs-Henseleit buffer was used as a blood substitute, which allowed for endocardial imaging utilizing 6.0 mm endoscopic video cameras inserted into the cardiac chambers. The hearts were perfused in Langendorff (retrograde) and/or working (physiologic) mode. RESULTS: Eleven of 12 hearts achieved the following performance in working mode: peak left ventricular pressure of 21.5 to 75.8 mm Hg, with an average of 42.7 +/- 19.9 mm Hg. Intracardiac anatomical imaging was possible in all hearts, providing unique views of normal and pathological endocardial anatomy as well as biomedical device-heart interactions. CONCLUSIONS: We have described a unique isolated heart preparation with which we have successfully reanimated 11 human hearts deemed not viable for transplant, perfused them by working mode, and performed intracardiac anatomical imaging. This approach provides a novel means for obtaining images of functional human cardiac anatomy and various types of unique biomedical assessments.