Background and Aims to analyze the results of surgical correction of native arteriovenous fistula (AVF) aneurysms in hemodialysis patients. Method A retrospective observational study included 158 patients who underwent various surgical interventions. 87 patients (55.1%) underwent pre-emptive surgeries. 71 patients (44.9%) underwent surgeries after AVF thrombosis («on demand» surgery). In the presence of high-flow AVF or in a case of high risk of fistula vein rupture, aneurysmorrhaphy was performed, which was supplemented by transposition of the reconstructed vein – fig. 1. In a case of paraanastomotic stenosis of the vein, aneurysmorrhaphy was enhanced by arteriovenous anastomosis proximalization. In a case of local proximal or distal stenosis of the functional segment of the vein, aneurysmorrhaphy was supplemented with stenosis plastic using the wall of the resected aneurysm. In a case of prolonged proximal stenosis or totally thrombosed proximal aneurysm, the fistula blood flow was switched to v. basilica with its transposition. In the case of a totally thrombosed distal aneurysm, it was excised and proximal AVF was created. Results In the case of pre-emptive surgeries, secondary patency was 69% [95% CI 44.9; 84.2] after 4.8 years (maximum follow-up). In the case of on-demand surgeries the secondary patency was 45.6% [95% CI 23.6; 65.2] after 4.3 years (maximum follow-up) – fig. 2. HR (log rank test) pre-emptive vs. on demand surgeries 0.296 [95% CI 0.147; 0.592], inverse HR = 3.381 [95% CI 1.674; 6.827], p = 0.0002. The risk AVF function loss was lower in patients who received pre-emptive surgeries compared with patients who received on-demand surgery: 2.642 [95% CI 1.406; 4.519] versus 6.268 [95% CI 3.927; 9.49] per 100 patient-years, incidence rate ratio (IRR) = 0.422 [95% CI 0.207; 0.834] (inverse estimate IRR=2.372 [95% CI 1.2; 4.842]), p = 0.0127. The need for CVC was also lower in patients who received pre-emptive surgeries: 1.728 [95% CI 1.38; 2.136] versus 2.821 [95% CI 2.292; 3.434] per 10 patient-years, IRR=0.6125 [95% CI 0.4576; 0.8185] (inverse estimate IRR= 1.633 [95% CI 1.222; 2.185]), p = 0.0009. Moreover, the number of operations was significantly higher in patients who underwent pre-emptive surgeries: 4.207 [95% CI 3.654; 4.821] versus 2.963 [95% CI 2.421; 3.59] per 10 patient-years, IRR=1.42 [95% CI 1.124; 1.802] (inverse estimate IRR= 0.704 [95% CI 0.555; 0.89]), p=0.0031. In almost all cases, fistula vein aneurism has been associated with various hemodynamic disorders. The median volume blood flow Qa was 2.9 [interquartile range - IQR 1.9; 3.8] l/min., (minimum. 1 l/min., max. 4.5 l/min.). Reconstruction in most cases led to significant change in Qa (p<0.0001). After reconstruction, the Qa median was 1.8 [IQR 1.6; 2.1] l/min. (minimum 1.4 l/min., max. 2.1 l/min). It is noteworthy that in patients with low Qa values, Qa increased slightly, and at high values, it decreased significantly. However, additional methods of blood flow reducing were not used. The median of the Qa difference was -1.2 [IQR -1.9; -0.2] l/min. (minimum -2.7 l/min, max. 1 l/min.). Conclusion The indication for surgical treatment is not just aneurism, but its complications, the high risk of complications development or a combined pathology. Preventive surgical interventions can significantly extend the AVF patency and reduce the need for central venous catheters, however, this is achieved by significantly increasing the number of surgeries. The concept of routine monitoring of a normally functioning AVF by a surgeon should replace the concept of on-demand surgery in case of AVF thrombosis or development of other serious complications.
Background and Aims cardiopulmonary recirculation (CRP) is one of the most informative instrumental parameters, which are widely used to predict adverse cardiovascular events. The CRP is calculated on the basis of two indirectly measured estimates. We observe a significant variability in CRP, the reason for which we have tried to explain. Method The prospective study included 88 patients with native AVF. At the first stage, we evaluated the inter- and inner-observer agreement of AVF volume blood flow (Qa) measurement with color duplex ultrasound. Two specialists with 5-7 years of experience measured Qa twice on the brachial artery, twice on fistula vein, after that - twice measured cardiac output before HD and one time after HD. Ultrafiltration during HD was 1.9±0,5 l. Results We observed good concordance between measurements on the brachial arteria by one specialist (fig 1A) and by two specialists (fig. 1B). There was poor concordance between the brachial artery and the fistula vein, even if the measurement was performed by one specialist (fig. 1C). Qa measurement on the fistula vein has a low repeatability, even if the measurement was performed by one specialist: the variance is very high (fig. 1 D). We observed a good concordance between measurements (fig. 2A) and between specialists (fig. 2B) in CO assessment. The main pitfalls of CPR-based cardiovascular risk stratification are related to the fact that CO changes significantly after HD (fig. 3A), while Qa values remain relatively stable (fig. 3B): the QA before and after HD difference is statistically significant, but it is minimal. Median CO decrease was 13.4% (maximum 26.6%), while median of Qa decrease was 1.7% (maximum 6.1%). This leads to a significant increase of the CPR value after HD, which can reach 40%(!) in some patients (absolute increase – 0.11). Conclusion Qa assessment should be performed on the brachial artery. After HD, there is a significant decrease in cardiac output (even with moderate ultrafiltration) with relatively stable AVF volume blood flow. This leads to a significant increase of CPR value after HD in some patients. Assessment of CPR before HD may lead to underestimation of cardiovascular risk.
Background and Aims For many years we observed aging of HD population: the proportion older adults is increasing. These patients have extremely low kidney transplantation rate, so vascular access is not a temporary option, but an important factor until the end of life. At the same time in older adults life expectancy is lower and the risks of cardiovascular events are much higher than in the general population of HD patients. We analyzed the results of providing elderly patients with vascular access. Method The study included 618 patients (age ≥ 65) from the Moscow region CKD patients register. Results With the current practice, only about 60% of elderly patients begin HD within a year after the AVF creation (taking into account competing events) - fig. 1. The proportion of patients with brachiocephalic AVF was significantly higher than in younger patients: 41,3% vs. 16,4%. It is known that proximal AVF have a much greater tendency to increase the volume blood flow (and therefore – cardiopulmonary recirculation) than distal. Thus, elderly patients begin HD with a more adverse comorbid background. Therefore, elderly patients have an additional risk factor - the onset of HD after 65 years – fig 2. Paradoxically, but according to our data, patients who started HD after 65 years had a worse prognosis than patients who reached 65 while already on HD. At the same time, the onset of HD with CVC with the subsequent successful conversion to AVF was not associated with a significant increase in the risk of death («CVC-AVF» factor). Only if CVC remained the only vascular access («CVC» factor), the risk of death is increase significantly. This is indirect evidence in favor of the fact that in elderly patients, the AVF must be created closer to the expected start of HD. In adjusted model, the significant risk factors also were diabetes, systemic diseases (factor «Other») and comorbidity (CIRS score), but not age. Among patients who started HD with CVC, all patients received functional AVF or died within 11 months – fig. 3. Infections occur with the same frequency (CVC-AVF vs. AVF) and clinical manifestations of central venous insufficiency do not have time to occur during the expected life period in most patients: incidence rate ratio IRR 1.21 [0.91; 1.31] and IRR 1.11 [0.93; 1.19], respectively. Is a conversion of AVF to CVC can improve the outcomes in older adults? In some patients probably - yes. Since many elderly patients initially have heart failure and a reduced cardiac output (CO), the potential for compensating of AVF blood flow (Qa) is significantly less than in younger patients. We found that this leads to the fact that in the elderly, at a lower Qa value, a greater value of cardiopulmonary recirculation is noted. Even with a Qa value of 1.0-1.2 l/min, the Qa/CO value can reach ≈ 25%, which is associated with a significant risk of death. But there is good news: in the older adults some criteria are more informative than in the general population of HD patients: AUC-ROC of ejection fraction (EF), estimated pulmonary artery systolic pressure (ePASP) and Qa/CO – 0.821, 0.804 and 0.846, respectively vs. 0.654, 0.726 and 0.764. The bad news: the decision to convert from a functional AVF to a CVC is a very difficult choice. Specific indications are still not determined. We believe that it is necessary to consider the conversion from AVF to CVC in a case of decompensated heart failure, with EF<30-33% or ePASP>50-55 or Qa/CO>20-25%, if the reduction of Qa does not improve these parameters. In this case, conversion from CVC to AVF may improve the prognosis. Older patients require more careful monitoring than younger patients. Conclusion 1. The start of HD with CVC is not a problem in case of subsequent successful conversion to AVF. 2. The most important risk factors is comorbidity, starting of HD after 65 years, diabetes and only then - vascular access type. 3. Given all the facts, in the older adults we tend to create an AVF closer to start of HD than in the general HD population.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.