[Ultrasonography of the inferior vena cava (IVC) in the diagnosis and monitoring of therapy in patients with chronic congestive heart failure]

Radiological evaluation of caudal vena cava in domestic short­hair cats with regard to right heart failure diagnosis

Radiology, an imaging technique, is used in checking small animals for cardiovascular and respiratory disorders. Cardiovascular disease such as congestive heart failure, pericardial heart disease, heart worms and disease that cause injury and lesion in the right atrium may lead to an enlarged right side of the heart and as a result cause the enlargement of caudal vena cava (CVC). It is not possible to make a complete comparison of CVC size, due to variety in size of the cats but the ratio of CVC size to the other anatomical structures makes this possibility that we have a better estimation of CVC size. So the aim of this study was to evaluate the ratio of CVC size to aorta (Ao), width of fourth rib (R4) and also the thoracic vertebral length (VL) in 20 male healthy and 20 Domestic Shorthair (DSH) cats with right heart failure (RHF). To this end, the ratio of CVC size to posterior aorta (Ao), the ratio of CVC size to width of the forth rib, the ratio of CVC size to the length of thoracic vertebrae above the site of trachea bifurcation, CVC/VL of 20 RHF cats to CVC/VL of 20 healthy SHD cats, and also Ao/VL ratios were calculated. Statistical analysis showed significant difference in the CVC/Ao and CVC/R4 between healthy and RHF cats. CVC/VL was increased in RHF cats in comparison to healthy ones (P<0.05) while Ao/VL in right heart failure DSH cats was lower than that in healthy DSH cats. The results showed that right heart failure disease in cats may lead to increase in the CVC/Ao, CVC/R4 and CVC/VL parameters in comparison with healthy cats. According to this study, the method that is used to diagnose the right heart failure in dogs could be used for cats too.

Blood urea nitrogen to creatinine ratio is associated with congestion and mortality in heart failure patients with renal dysfunction

Renal dysfunction (RD) and venous congestion are related and common in heart failure (HF). Studies suggest that venous congestion may be the primary driver of RD in HF. In this study, we sought to investigate retrospectively the relationship between common measures of renal function with caval congestion and mortality among outpatients with HF and RD. We reviewed data from 103 HF outpatients (45 males, mean age 74 years, ejection fraction 41.8 ± 11.6 %) with estimated glomerular filtration rate (eGFR) of < 60 ml/min in a single centre. During an ambulatory visit, all patients underwent blood test and ultrasonography of the inferior vena cava (IVC). Caval congestion was defined as IVC with both dilatation and impaired collapsibility. The best values of renal metrics in predicting caval congestion were determined with receiver-operating characteristic analysis. The BUN/Cr ratio is moderately correlated with IVC expiratory maximum diameter (r = 0.31, p < 0.0007). In a multiple logistic regression model, BUN/Cr > 25.5 (adjusted OR 2.98, p 0.015) and eGFR ≤ 45.8 (adjusted OR 5.38, p 0.002) identify patients at risk for caval congestion; a BUN/Cr > 23.7 was the best predictor of impaired collapsibility (adjusted OR 4.41, p 0.001). a BUN/Cr > 25.5 (HR 2.19, 95 % CI 1.21-3.94, p < 0.001) and NYHA class 3 (HR 2.91, 95 % CI 1.60-5.31, p < 0.0005) were independent risk factors associated with all-cause death during a median follow-up of 31 months. In outpatients with HF and RD, a higher BUN/Cr and lower eGFR are reliable renal biomarkers for caval congestion. The BUN/Cr is associated with long-term mortality and may help to stratify HF severity.

Inferior vena cava diameter change after intravenous furosemide in patients diagnosed with acute decompensated heart failure

PURPOSE

Measurement of the inferior vena cava (IVC) diameters may improve decision-making for patients hospitalized with acute decompensated heart failure. Nevertheless, little is known about how the IVC is affected by loop diuretics. We sought to determine if bolus infusions of intravenous furosemide affect IVC diameters measured by hand-carried ultrasonography.

METHODS

We conducted a prospective cohort study at a public teaching hospital from September 2009 through June 2010. Physician investigators performed IVC ultrasonography on a convenience sample of 70 hospitalized adults who were prescribed intravenous furosemide for the diagnosis of acute decompensated heart failure.

RESULTS

Participants' median baseline IVC diameter was 2.38 cm (interquartile range, 1.91-2.55 cm). At 1-2 hours after furosemide, IVC diameters decreased an average of 0.21 cm (95% CI, 0.13-0.29 cm) and remained significantly below baseline at 2-3 hours after furosemide by an average of 0.15 cm (95% CI, 0.07-0.22 cm).

CONCLUSIONS

IVC diameters of adults diagnosed with acute decompensated heart failure become measurably smaller after single doses of intravenous furosemide. Whether this represents a true change in volume status has not been studied.

Radiographic evaluation of caudal vena cava size as a useful parameter for the diagnosis of heart disease in dairy cattle

To quantify the radiographic parameters of the caudal vena cava (CVC) in healthy cattle and demonstrate their clinical usefulness, the present study compared the ratios of the diameter of the thoracic CVC to the diameter of the aorta (Ao) and length of the thoracic vertebrae (VL), which are all positioned in the same intercostal space, in 81 healthy control cattle (43 growing, 38 adult) and 10 cattle with heart disease. The average diameter of the CVC (CVCave) was correlated with the size of the Ao and VL in the control cows. Although the diameter and pulsation index of the CVC differed significantly between the growing and adult cows, the ratios of CVC/Ao and CVC/VL were fixed values for both the growing and mature cattle. However, in the cattle with heart disease, the pulsation index of the CVC was significantly lower or there was absence of pulsation due to a dilated CVC, and the ratio of CVCave/Ao and CVCave/VL were significantly higher than those in the healthy cattle.

Measurement of volumetric flow

OBJECTIVE

The purpose of this study was to evaluate a 3-dimensional (3D) sonographic method for the measurement of volumetric flow under conditions of known flow rates and Doppler angles.

METHODS

A GE/Kretz Voluson 730 system (GE Healthcare, Milwaukee, WI) and RAB2-5 probe were used to acquire 3D Doppler measurements in a custom flow phantom. Blood-mimicking fluid circulated by a computer-controlled pump provided a range of flow velocities (2-15 mL/s). A 6-axis positioning system maneuvered the ultrasound probe through a range of angles (40 degrees-70 degrees and 110 degrees -140 degrees) with respect to the tube (orthogonal to the tube being 90 degrees). Volume data sets were obtained spanning 29 degrees lateral and 20 degrees elevational angles encompassing the flow tube in a scanning time of less than 10 seconds. Power Doppler data were used to correct for partial volume effects.

RESULTS

Using a single angle (110 degrees) with respect to the flow tube, measured and actual volume flow rates were within the 95% confidence interval over the full range of flow rates. At flow rates of 5 and 10 mL/s, the measured volume flow rates were all within +/-15% of actual values for the range of angles tested and also stayed within the 95% confidence interval.

CONCLUSIONS

Direct comparisons of volume flow rates estimated with 3D sonography and known flow rates showed that the method has good accuracy. Subsequent comparisons under pulsatile and in vivo conditions will be needed to verify this performance for clinical applications.