SPC365

Assessment of Myocardial Blood Flow Changes using [13N]NH3 PET-CT in Chronic Total Coronary Occlusion Patients undergoing PCI

Session: SESSÃO DE COMUNICAÇÕES ORAIS 13 - FRONTEIRAS INOVADORAS NO DIAGNÓSTICO DA DOENÇA ARTERIAL CORONÁRIA E AVALIAÇÃO DE RISCO: DA IMAGEM AVANÇADA AOS RESULTADOS CLÍNICOS
Speaker: Tomás M. Carlos

Congress: CPC 2025
Topic: B. Imaging
Theme: 03. Imaging
Subtheme: 03.4 Nuclear Imaging
Session Type: Comunicações Orais
FP Number: ---
Authors: Tomás M. Carlos; Inês Brito e Cruz; Luís Leite; Gustavo Campos; Rodolfo Silva; Andreia Gomes; Miguel Castelo-Branco; Antero Abrunhosa; Lino Gonçalves; Maria João Ferreira

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">Introduction:&nbsp;</span></span></strong></span></span><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">In chronic total coronary occlusions (CTO) the affected myocardium becomes vascularized by collateral networks from adjacent coronary vessels. The perfusion in the CTO territory is decreased, mainly in stress conditions, but also in remote areas because of the &ldquo;steal phenomenon&rdquo;. There is limited data about changes in quantitative perfusion in these patients after percutaneous coronary intervention (PCI). Our aim was to assess changes in myocardial blood flow (MBF), measured in mL.min<sup>-1</sup>.g<sup>-1</sup>, in both CTO and remote myocardium territories after PCI, using [<sup>13</sup>N]NH<sub>3 </sub>positron emission tomography computed tomography (PET-CT).</span></span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">Methods:&nbsp;</span></span></strong></span></span><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">We performed a single-centre prospective study involving patients with CTO who underwent myocardial quantitative perfusion assessment using [<sup>13</sup>N]NH<sub>3 </sub>both before and after PCI. Patients were excluded if they lacked indication for PCI based on current guidelines, had inadequate follow-up, insufficient data or did not complete imaging either before or after the procedure.</span></span></span></span></p>

<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">Results:&nbsp;</span></span></strong></span></span><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">Within our cohort of 19 patients with CTO who underwent PCI, 13 were submitted to pre and post- procedural assessment with [<sup>13</sup>N]NH<sub>3</sub> PET-CT. The mean age was 68 years (&plusmn; 4.3) and 76.9% were male. After PCI, hyperaemic MBF (hMBF) increased in CTO territory (&Delta; 0.36 &plusmn; 0.34, p=0.003), whereas no statistically significant difference was observed in the remote myocardium (&Delta; 0.05 &plusmn; 0.21, p=0.423). At rest, MBF (rMBF) did not significantly change after PCI in either CTO territory (</span></span><span style="font-size:12.0pt"><span style="background-color:white"><span style="font-family:&quot;Times New Roman&quot;,serif"><span style="color:#202124">&Delta;</span></span></span></span><span style="font-size:12.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif"> 0.06 &plusmn; 0.21, <em>p</em>=0.351) or remote myocardium (</span></span><span style="font-size:12.0pt"><span style="background-color:white"><span style="font-family:&quot;Times New Roman&quot;,serif"><span style="color:#202124">&Delta;</span></span></span></span><span style="font-size:12.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif"> 0.04 &plusmn; 0.16, <em>p</em>=0.444). Myocardial flow reserve also showed no differences between the two groups.&nbsp; Alterations in MBF in the CTO territory exhibited a strong linear correlation with the corresponding changes in the remote myocardium (hMBF: r=0.732, <em>p</em>=0.004; rMBF: r=0.958, <em>p</em>&lt;0.001).</span></span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">Conclusion:&nbsp;</span></span></strong></span></span><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">PCI reestablishes normal coronary perfusion and may lead to the regression of the collateral network. In our study, myocardial perfusion increased in the CTO territory in stress conditions, with no differences being observed at rest or in the remote myocardium in both conditions. Interestingly, a more significant improvement in CTO territory perfusion was associated with a greater increase in MBF in remote myocardium, likely reflecting the reduction of a previously larger coronary &ldquo;steal phenomenon&rdquo; after PCI.</span></span></span></span></p>