Coronary Intervention
Intact Parathyroid Hormone in Hemodialysis Patients Undergoing Percutaneous Coronary Intervention ― Is It Just a Marker or a Diamond in the Rough? ―
2023 年 87 巻 2 号 p. 256-257
詳細
2023 年 87 巻 2 号 p. 256-257
Improving the prognosis of hemodialysis (HD) patients is still challenging, even in contemporary medicine.1 Cardiovascular disease is the primary cause of death; hence, cardiologists struggle with this tough category of patients. We had high hopes of the effect of drug-eluting stents (DES),2 and then recently the limitation of “local treatment” has been called.3
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Coronary calcification is one of the noteworthy characteristics of HD patients, and hormonal abnormality plays a crucial role. In this issue of the Journal, Kobayashi et al4 focus on the intact parathyroid hormone (iPTH) level in HD patients who underwent percutaneous coronary intervention (PCI) using DES. Briefly, the higher iPTH group had less adequate stent expansion due to more severe calcification of the coronary artery, resulting in a poor clinical outcome. This paper is worthy and admirable, highlighting at least 2 hot topics.
First, is iPTH just a vital marker for the poor prognosis of HD patients undergoing PCI or could it be a potential target for treatment? The iPTH levels are controlled by a complex feedback loop of calcium and phosphorus levels in the blood to the parathyroid glands. In patients on HD, long-term secondary hyperparathyroidism causes hypercalcemia and ectopic calcification, which is one of the reasons for the extreme calcification in HD patients. Nevertheless, in the guideline of chronic kidney disease – mineral and bone disorder (CKD-MBD),5 the treatment priority of iPTH is relatively low compared with other parameters such as phosphorus and calcium, based on their prognostic impact. In the Evaluation of Cinacalcet Hydrochloride Therapy to Lower Cardiovascular Events (EVOLVE) trial, cinacalcet, a medication for secondary hyperparathyroidism, did not significantly reduce the risk of death or major cardiovascular events.6 In addition, the treatment target level of iPTH remains to be determined. Zhou et al7 reported that the relationship between serum iPTH and death appears to be a U-shaped curve. The optimal serum iPTH level, which confers the lowest risk of all-cause death, ranged from 150 pg/mL to 450 pg/mL in Chinese incident HD patients. Villa-Bellosta et al reported that a decrease in ∆iPTH was associated with higher mortality in HD patients with median iPTH values within the guideline-recommended range.8 Thus, the treatment target level of iPTH would still be controversial, and few trials have verified the effect of strict management of CKD-MBD, including iPTH, on clinical outcomes of HD patients.9 Kobayashi et al suggest a new cutoff value of iPTH, 127 pg/mL, for predicting clinical outcomes in contemporary HD patients who undergo PCI.4 That is relatively lower than in previous reports, which will again draw attention to the importance of iPTH in this high-risk subset. Further studies with the collaboration of cardiologists and nephrologists are warranted to answer this tricky clinical question.
Second, what would be the optimal PCI strategy in HD patients showing high iPTH levels? Kobayashi et al report that the high iPTH group had a higher calcium score and number of calcified nodules, and lower stent expansion index, and symmetry index evaluated by intravascular ultrasound (IVUS).4 Accordingly, appropriate lesion preparation by aggressive atherectomy using specific devices such as rotational atherectomy,10 orbital atherectomy,11 intravascular lithotripsy12 following adjunctive DES implantation or drug-coated balloon (DCB) dilatation would be essential.
The effect of the iPTH level on coronary calcification assessed by IVUS and the long-term clinical outcomes in HD patients undergoing PCI shown in the present study suggest the possibility of “aggressive, systematic management of secondary hyperparathyroidism” by phosphate binders, vitamin D derivatives, calcimimetics, and parathyroidectomy, together with “optimal local therapy” by meticulous PCI with aggressive lesion preparation following DES/DCB would be key to better clinical scenarios in HD patients with coronary artery disease in contemporary practice.
Under the slogan of “think globally, act locally,” iPTH might be a diamond in the rough, and the concept of a total management approach would create waves for the treatment of HD patients undergoing PCI (Figure).
The concept of a total management approach for hemodialysis patients undergoing PCI; “Aggressive systemic management” and “Optimal local therapy”. DES, drug-eluting stent; DCB, drug-coated balloon; iPTH, intact parathyroid hormone; PCI, percutaneous coronary intervention.
