Computing pulsatile blood flow of coronary artery under incomplete boundary conditions.

BACKGROUND: Accurate measurement of pulsatile blood flow in the coronary arteries enables coronary wave intensity analysis, which can serve as an indicator for assessing coronary artery physiology and myocardial viability. Computational fluid dynamics (CFD) methods integrating coronary angiography images and fractional flow reserve (FFR) offer a novel approach for computing mean coronary blood flow. However, previous methods neglect the inertial effect of blood flow, which may have great impact on pulsatile blood flow calculation. To improve the accuracy of pulsatile blood flow calculation, a novel CFD based method considering the inertia term is proposed. METHODS: A flow resistance model based on Pressure-Flow vs.Time curves is proposed to model the resistance of the epicardial artery. The parameters of the flow resistance model can be fitted from the simulated pulsating flow rates and pressure drops of a specific mode. Then, pulsating blood flow can be calculated by combining the incomplete pressure boundary conditions under pulsating conditions which are easily obtained in clinic. Through simulation experiments, the effectiveness of the proposed method is validated in idealized and reconstructed 3D model of coronary artery. The impacts of key parameters for generating the simulated pulsating flow rates and pressure drops on the accuracy of pulsatile blood flow calculation are also investigated. RESULTS: For the idealized model, the previously proposed Pressure-Flow model has a significant leading effect on the computed blood flow waveform in the moderate model, and this leading effect disappears with the increase of the degree of stenosis. The improved model proposed in this paper has no leading effect, the root mean square error (RMSE) of the proposed model is low (the left coronary mode:≤0.0160, the right coronary mode:≤0.0065) for all simulated models, and the RMSE decreases with an increase of stenosis. The RMSE is consistently small (≤0.0217) as the key parameters of the proposed method vary in a large range. It is verified in the reconstructed model that the proposed model significantly reduces the RMSE of patients with moderate stenosis (the Pressure-Flow model:≤0.0683, the Pressure-Flow vs.Time model:≤0.0297), and the obtained blood flow waveform has a higher coincidence with the simulated reference waveform. CONCLUSIONS: This paper confirms that ignoring the effect of inertia term can significantly affect the accuracy of calculating pulsatile blood flow in moderate stenosis lesions, and the new method proposed in this paper can significantly improves the accuracy of calculating pulsatile blood flow in moderate stenosis lesions. The proposed method provides a convenient clinical method for obtaining pressure-synchronized blood flow, which is expected to facilitate the application of waveform analysis in the diagnosis of coronary artery disease.

Improvement of Symptoms and Quality of Life After Successful Percutaneous Coronary Intervention for Chronic Total Occlusion in Elderly Patients.

Background Data regarding the impact of successful chronic total occlusion treated with percutaneous coronary intervention (CTO-PCI) on symptoms and quality of life (QOL) in elderly patients (≥75 years) are unknown. This prospective study aimed to assess whether successful CTO-PCI could improve the symptoms and QOL in elderly patients (≥75 years). Methods and Results Consecutive patients who underwent elective CTO-PCI were prospectively enrolled and subdivided into 3 groups based on age: age<65 years, 65 years≤age<75 years, and age≥75 years. The primary outcomes included symptoms, as assessed with the New York Heart Association functional class and Seattle Angina Questionnaire, and QOL, as assessed with the 12-Item Short-Form Health Survey questionnaire, at baseline, 1 month, and 1 year after successful CTO-PCI. Of 1076 patients with CTO, 101 were age≥75 years (9.39%). Hemoglobin, estimated glomerular filtration rate, and left ventricular ejection fraction levels all decreased with increasing age, and NT-proBNP (N-terminal pro-B-type natriuretic peptide) increased. The proportion of dyspnea and coronary lesions, including multivessel disease, multi-CTO lesion, and calcification were higher in elderly patients. Procedural success rate, intraprocedural complications, and in-hospital major adverse cardiac events were not statistically different in the 3 groups. Importantly, symptoms, including dyspnea and angina, were markedly improved regardless of age at 1-month and 1-year follow-up (P<0.05). Likewise, successful CTO-PCI significantly improved QOL at 1-month and 1-year follow-up (P<0.01). Additionally, the incidence of major adverse cardiac events and all-cause mortality at 1-month and 1-year follow-up was not statistically different in the 3 groups. Conclusions Successful PCI was beneficial and feasible to improve symptoms and QOL in patients ≥75 years of age with CTO.

Benefits of successful percutaneous coronary intervention in chronic total occlusion patients with diabetes.

BACKGROUND: Diabetes was commonly seen in chronic total occlusion (CTO) patients but data regarding the impact of successful percutaneous coronary intervention (PCI) on clinical outcome of CTO patients with diabetes was controversial. And importantly, no studies have compared quality of life (QOL) after CTO-PCI in patients with and without diabetes. METHODS: Consecutive patients undergoing elective CTO-PCI were prospectively enrolled from Apr. 2018 to May 2021. Patients were subdivided into 2 groups: Diabetes and No Diabetes. Detailed baseline characteristics, assessment of symptoms and QOL, angiographic and procedural details, in-hospital complications, and 1 month and 1 year follow-up data were collected. These data were analyzed accordingly for risk predictors of clinical outcome in patients who have diabetes and received successful CTO-PCI. RESULTS: A total of 1076 patients underwent CTO-PCI attempts. Diabetes was present in 374 (34.76%) patients, who had more hypertension, previous PCI and stroke. Regarding the coronary lesions, diabetic patients suffered more LCX lesion, multivessel disease, number of lesions per patient, blunt stump, calcification and higher J-CTO score (p < 0.05). In-hospital major adverse cardiac event (MACE) (4.13% vs. 5.35%; p = 0.362) was similar in the two groups. At 1 month and 1 year follow-up after successful CTO-PCI, the incidence of MACE and all-cause mortality were also similar in the two groups (p > 0.05). Number of lesions per patient was an independent risk factor of MACE and all-cause mortality (p < 0.001) 1 year after successful CTO-PCI. Symptom and QOL were markedly improved regardless of diabetes both at 1 month and 1 year follow-up, and importantly, patients with diabetes showed similar degrees of improvement to those without diabetes (P > 0.05). CONCLUSIONS: Successful CTO-PCI could represent an effective strategy improving clinical outcome, symptoms and QOL in CTO patients with diabetes.

Percutaneous coronary intervention improves quality of life of patients with chronic total occlusion and low estimated glomerular filtration rate.

Background: A low estimated glomerular filtration rate (eGFR <90 mL/min/1.73 m2) is widely recognized as a risk factor for major adverse cardiac events (MACE) after percutaneous coronary intervention (PCI) for chronic total occlusion (CTO). However, the impact of successful CTO-PCI on quality of life (QOL) of patients with low eGFR remains unknown. Objectives: The aim of this prospective study was to assess the QOL of CTO patients with low eGFR after successful PCI. Methods: Consecutive patients undergoing elective CTO-PCI were prospectively enrolled and subdivided into four groups: eGFR ≥90 mL/min/1.73 m2 (n = 410), 90 > eGFR ≥ 60 mL/min/1.73 m2 (n = 482), 60 > eGFR ≥ 30 mL/min/1.73 m2 (n = 161), and eGFR <30 mL/min/1.73 m2 (n = 23). The primary outcomes included QOL, as assessed with the European Quality of Life-5 Dimensions (EQ-5D) questionnaire, and symptoms, as assessed with the Rose Dyspnea Scale (RDS) and Seattle Angina Questionnaire (SAQ), at 1 month and 1 year after successful PCI. Results: With the decline of eGFR, CTO patients were more likely to present with comorbidities of hypertension, diabetes, hyperuricemia, and previous stroke, in addition to lower hemoglobin levels and left ventricular ejection fraction (p < 0.05). Low eGFR was associated with greater incidences of in-hospital pericardiocentesis, major bleeding, acute renal failure, and subcutaneous hematoma, but not in-hospital MACE (p < 0.05). Symptoms of dyspnea and angina were alleviated in all CTO patients with eGFR ≥30 mL/min/1.73 m2 at 1 month and 1 year after successful CTO-PCI, but only at 1 month for those with eGFR <30 mL/min/1.73 m2 (p < 0.01). Importantly, QOL was markedly improved at 1 month and 1 year after successful PCI (p < 0.01), notably at a similar degree between patients with low eGFR and those with normal eGFR (p > 0.05). Conclusion: Successful PCI effectively improved symptoms and QOL of CTO patients with low eGFR.