The importance of concomitant mitral regurgitation for estimates of mitral valve area by pressure half time in patients with chronic rheumatic heart disease.

AIMS: Aim was to study how concomitant mitral regurgitation (MR) assessed by qualitative and quantitative methods influence mitral valve area (MVA) calculations by the pressure half time method (MVAPHT) compared to reference MVA (planimetry) in patients with rheumatic heart disease. METHODS AND RESULTS: In 72 patients with chronic rheumatic heart disease, MVAPHT was calculated as 220 divided by the pressure half time of the mitral early inflow Doppler spectrum. Direct measurement by planimetry was used as reference MVA and was mean (SD) 0.99 (0.69-1.99) cm2. Concomitant MR was present in 82%. MR severity was assessed qualitatively in all, semi-quantitatively by measuring the vena contracta width in 58 (81%), and quantitatively by calculation of the regurgitant volume in 28 (39%). MVA was significantly underestimated by MVAPHT, with increasing MR. In regression analyses MVAPHT underestimated MVA by 0.19 cm2 per higher grade of MR severity in qualitative assessment, and by 0.12-0.13 cm2 per mm larger vena contracta width and 10 ml larger regurgitant volume, respectively. The presented associations were more evident when i) MR severity was quantified compared to qualitative assessment and ii) reference measurements were made by three-dimensional transoesophageal recordings compared to transthoracic recordings. CONCLUSION: MVAPHT underestimated mitral valve area compared to planimetry in patients with MS and concomitant MR. This study highlights the importance of taking the MR severity into account when evaluating MVA based on the PHT method. Direct measurements should be included in clinical decision making.

Short-term outcome after open-heart surgery for severe chronic rheumatic heart disease in a low-income country, with comparison with an historical control group: an observational study.

OBJECTIVES: Rheumatic heart disease (RHD) is a major burden in low-income and middle-income countries (LMICs). Cardiac surgery is the only curative treatment. Little is known about patients with severe chronic RHD operated in LMICs, and challenges regarding postoperative follow-up are an important issue. At Tikur Anbessa Specialised Hospital, Addis Ababa, Ethiopia, we aimed to evaluate the course and 12-month outcome of patients with severe chronic RHD who received open-heart surgery, as compared with the natural course of controls waiting for surgery and undergoing only medical treatment. METHODS: Clinical data and outcome measures were registered in 46 patients operated during five missions from March 2016 to November 2019, and compared with the first-year course in a cohort of 49 controls from the same hospital's waiting list for surgery. Adverse events were death or complications such as stroke, other thromboembolic events, bleeding, hospitalisation for heart failure and infectious endocarditis. RESULTS: Survival at 12 months was 89% and survival free from complications was 80% in the surgical group. Despite undergoing open-heart surgery, with its inherent risks, outcome measures of the surgical group were non-inferior to the natural course of the control group in the first year after inclusion on the waiting list (p≥0.45). All except six surgical patients were in New York Heart Association class I after 12 months and 84% had resumed working. CONCLUSIONS: Cardiac surgery for severe chronic RHD is feasible in LMICs if the service is structured and planned. Rates of survival and survival free from complications were similar to those of controls at 12 months. Functional level and resumption of work were high in the surgical group. Whether the patients who underwent cardiac surgery will have better long-term prognosis, in line with what is known in high-income countries, needs to be evaluated in future studies.

Is the use of hydroxyethyl starch as priming solution during cardiac surgery advisable? A randomized, single-center trial.

INTRODUCTION: The use of cardiopulmonary bypass (CPB) leads to increased fluid filtration and edema. The use of artificial colloids to counteract fluid extravasation during cardiac surgery is controversial. Beneficial effects on global fluid loading, leading to better cardiac performance and hemodynamics, have been claimed. However, renal function and coagulation may be adversely affected, with unfavorable impact on outcome following cardiac surgery. METHODS: Forty patients were randomly allocated to study groups receiving either acetated Ringer's solution (CT group) or hydroxyethyl starch (HES group, Tetraspan®) as CPB priming solution. Fluid balance, bleeding and hemodynamics, including cardiac output, were followed postoperatively. The occurrence of acute kidney injury was closely registered. RESULTS: Two patients were excluded from further analyzes due to surgical complications. Fluid accumulation was attenuated in the HES group (3374 (883) ml) compared with the CT group (4328 (1469) ml) (p=0.024). The reduced perioperative fluid accumulation was accompanied by an increased cardiac index immediately after surgery (2.7 (0.4) L/min/m2 in the HES group and 2.1 (0.3) L/min/m2 in the CT group (p<0.001)). No increase in bleeding could be demonstrated in the HES group. Three patients, all of them in the HES group, experienced acute kidney injury postoperatively. CONCLUSIONS: CPB priming with HES solution lowers fluid loading during bypass and improves cardiac function in the early postoperative period. The manifestation of acute kidney injury exclusively in the HES group of patients raises doubts about the use of HES products in conjunction with cardiac surgery. ( https://clinicaltrials.gov/ct2/show/NCT01511120 ).

Elevated flow rate during cardiopulmonary bypass is associated with fluid accumulation.

OBJECTIVE: High flow rates during cardiopulmonary bypass are assumed to increase fluid accumulation. This study aimed to determine whether two different flow rates during cardiopulmonary bypass alter the intraoperative fluid balance and extravasation rate. METHODS: Sixteen pigs underwent 60 minutes of normothermic bypass, followed by 90 minutes of hypothermic bypass. A high-flow group (HF group, n = 8) had a cardiopulmonary bypass flow rate of 110 mL x kg(-1) x min(-1) and a low-flow group (LF group, n = 8) had a rate of 80 mL x kg(-1) x min(-1). Blood chemistry, hemodynamic parameters, plasma and interstitial colloid osmotic pressure, net fluid balance, plasma volume, fluid extravasation rate, and total tissue water content were measured or calculated. Results are presented as mean (standard deviation). RESULTS: The average net fluid balance during cardiopulmonary bypass was 1.02 (0.25) and 0.73 (0.23) mL x kg(-1) x min(-1) in the HF group and LF group, respectively (P < .05). The average fluid extravasation rate was 0.98 (0.22) and 0.77 (0.22) mL x kg(-1) x min(-1) in the HF group and the LF group (P = .07). Total water content was higher in the kidneys (P < .05) and tended to be higher in the lungs (P = .05), liver (P = .07), and brain (P = .07) of the HF group than in those of the LF group. The between-group differences in net fluid balance and fluid extravasation rate were present during the first 30 minutes of normothermic cardiopulmonary bypass. Thereafter, the values stabilized and remained similar in the two groups. Plasma volume and systemic vascular resistance differed between the groups. CONCLUSION: Cardiopulmonary bypass flow rate of 110 mL x kg(-1) x min(-1) was associated with higher positive net fluid balance and fluid extravasation rate than 80 mL x kg(-1) x min(-1). The effect was mainly observed in the initial phase of cardiopulmonary bypass.

Cold-induced fluid extravasation during cardiopulmonary bypass in piglets can be counteracted by use of iso-oncotic prime.

OBJECTIVE: Hypothermic cardiopulmonary bypass is associated with increased fluid extravasation. This study aimed to compare whether iso-oncotic priming solutions, in contrast to crystalloids, could reduce the cold-induced fluid extravasation during cardiopulmonary bypass in piglets. METHODS: Three groups were studied: the control group (CT group; n = 10), the albumin group (Alb group; n = 7), and the hydroxyethyl starch group (HES group; n = 7). Prime (1000 mL) and supplemental fluid were acetated Ringer solution, 4% albumin, and 6% hydroxyethyl starch, respectively. After 1 hour of normothermic cardiopulmonary bypass, hypothermic cardiopulmonary bypass (cooling to 28 degrees C within 15 minutes) was initiated and continued to 90 minutes. Fluid needs, plasma volume, changes in colloid osmotic pressure in plasma and interstitial fluid, hematocrit levels, and tissue water content were recorded, and protein masses and fluid extravasation rates were calculated. RESULTS: Colloid osmotic pressure in plasma decreased immediately after the start of cardiopulmonary bypass in the CT group but remained stable in the Alb and HES groups. Colloid osmotic pressure in interstitial fluid tended to decrease in the CT group and remained unchanged in the Alb group, whereas a slight increase was observed in the HES group. Immediately after the start of cooling, fluid extravasation rates increased from 0.15 +/- 0.10 to 0.64 +/- 0.12 mL . kg -1 . min -1 in the CT group, whereas no such increase was observed in the Alb and HES groups. The changes in fluid extravasation rates were reflected by corresponding changes in tissue water content. CONCLUSION: The use of albumin or hydroxyethyl starch as prime to preserve the colloid osmotic pressure during cardiopulmonary bypass causes a reduction in the cold-induced fluid extravasation compared with that seen with crystalloids. Albumin seems more effective than hydroxyethyl starch to limit cold-induced fluid shifts during cardiopulmonary bypass.