2.1

Study design and participants

All patients with a CTO considered for percutaneous revascularization at the VU University Medical Center are analyzed in a dedicated screening and treatment program and a prospective database of all patients is maintained. All consecutive patients between January 2013 and April 2016 with a CTO of the RCA that were analyzed with CMR prior and three months after successful PCI CTO RCA, were included in the study. As part of a clinical dedicated CTO program, follow-up CMR after successful PCI CTO was performed routinely and independently from symptoms. All patients provided written informed consent and the study was approved by the institutional ethics committee.

2.2

Angiographic CTO characteristics

Two experienced CTO operators (PK and AN) assessed all dual arterial invasive coronary angiograms to determine angiographic CTO- and RCA side branch characteristics. A CTO was defined as an occlusion on invasive coronary angiography with no true lumen antegrade flow (TIMI Flow 0). Angiographic CTO morphology was evaluated in accordance with the J-CTO score. Collateral connection score was scored as; no visible connection (CC0), thread-like connection (CC1), or small branch like connection (CC2), and the extent of collateral flow was graded according to the Rentrop and Cohen classification. An RVB was defined as a side branch of the RCA supplying the RV territory on invasive coronary angiography originating from proximal, mid, or distal RCA. All side branches from the right posterolateral or right posterior descending artery were not considered as RVB. Diameter and TIMI flow of all RVBs were assessed on the first and last angiographic images of the procedure. An RVB with a diameter ≥ 1 mm and antegrade filling pattern ≥ TIMI flow grade II was deemed clinically significant. In case of post-procedural RVB occlusion ( Fig. 1 ), the etiology (i.e. dissection/stent implant) for side branch occlusion was documented. Development of a pre-procedural occluded or non-significant RVB (<1 mm) into an RVB with a diameter (≥ 1 mm) and TIMI flow ≥ II after PCI, was defined as RVB recruitment ( Fig. 1 ). Coronary recanalization was performed either by antegrade wire escalation (AWE), antegrade dissection and re-entry (ADR), retrograde wire escalation (RWE), or retrograde dissection and re-entry (RDR). Procedural success was defined as <30% diameter stenosis and TIMI flow grade III.

Invasive coronary angiography of two PCI CTO procedures illustrating right ventricular side branch loss and gain. Panel A shows a completely occluded RCA with one clinically significant RVB. The CTO was successfully crossed using an RDR technique; the concomitant dissection plane resulted in occlusion of the RVB (B). Panel C displays a CTO RCA of a patient with no clinically significant RVBs. However, the restoration of antegrade blood flow after PCI CTO using AWE resulted in recruitment of an RVB (D). PCI; percutaneous coronary intervention, CTO; chronic total occlusion, RCA; right coronary artery, RVB; right ventricular branch, RDR; retrograde dissection re-entry, AWE; antegrade wire escalation.

2.3

CMR protocol and image analysis

CMR was performed on a 1.5-T scanner (Avanto, Siemens, Erlangen, Germany) before and approximately 12 weeks after PCI CTO RCA. Functional imaging was performed using an ECG-gated, balanced steady-state free precession sequence in four-, three-, and two-chamber long-axis and short-axis orientations during mild expiration (typical parameters: TR/TE 3.2/1.5 ms, flip angle ~75°, voxel size 1.4 × 1.4 × 5.0 mm, temporal resolution 35–50 ms).

Cardiac magnetic resonance analysis was performed using dedicated software (qMass v7.6, Medis, Leiden, the Netherlands). CMR images were assessed by two experienced observers (PD and SB) who were blinded to the time point of CMR examinations (baseline versus follow-up) and clinical data. Right ventricle endocardial borders were manually delineated on end diastolic and end systolic cine short-axis images ( Fig. 2 ). Right ventricular end diastolic volume (RVEDV), right ventricular end systolic volume (RVESV), and RVEF were automatically calculated according to endocardial borders.

Cine short-axis CMR images. To determine right ventricular function prior and after PCI CTO, right ventricle endocardial borders were manually delineated on end diastolic (A) and end systolic (B) cine short-axis images. CMR; cardiac magnetic resonance imaging. Other abbreviations as Fig. 1 .

2.4

Statistical analyses

Continuous variables are presented as mean values ± standard deviation (SD), whereas categorical variables are expressed as actual numbers with percentages. Continuous variables of paired data were compared with the paired sample t-test or Wilcoxon test, depending on the distribution pattern, whereas differences between multiple groups were compared with the One-Way ANOVA test for normally distributed data and with the Kruskal Wallis test if there was a non-normal distribution. A level of p < 0.05 was considered significant. Statistical analyses were performed using SPSS software (IBM SPSS Statistics 22.0, Chicago, IL).

2.1

Study design and participants

All patients with a CTO considered for percutaneous revascularization at the VU University Medical Center are analyzed in a dedicated screening and treatment program and a prospective database of all patients is maintained. All consecutive patients between January 2013 and April 2016 with a CTO of the RCA that were analyzed with CMR prior and three months after successful PCI CTO RCA, were included in the study. As part of a clinical dedicated CTO program, follow-up CMR after successful PCI CTO was performed routinely and independently from symptoms. All patients provided written informed consent and the study was approved by the institutional ethics committee.

2.2

Angiographic CTO characteristics

Two experienced CTO operators (PK and AN) assessed all dual arterial invasive coronary angiograms to determine angiographic CTO- and RCA side branch characteristics. A CTO was defined as an occlusion on invasive coronary angiography with no true lumen antegrade flow (TIMI Flow 0). Angiographic CTO morphology was evaluated in accordance with the J-CTO score. Collateral connection score was scored as; no visible connection (CC0), thread-like connection (CC1), or small branch like connection (CC2), and the extent of collateral flow was graded according to the Rentrop and Cohen classification. An RVB was defined as a side branch of the RCA supplying the RV territory on invasive coronary angiography originating from proximal, mid, or distal RCA. All side branches from the right posterolateral or right posterior descending artery were not considered as RVB. Diameter and TIMI flow of all RVBs were assessed on the first and last angiographic images of the procedure. An RVB with a diameter ≥ 1 mm and antegrade filling pattern ≥ TIMI flow grade II was deemed clinically significant. In case of post-procedural RVB occlusion ( Fig. 1 ), the etiology (i.e. dissection/stent implant) for side branch occlusion was documented. Development of a pre-procedural occluded or non-significant RVB (<1 mm) into an RVB with a diameter (≥ 1 mm) and TIMI flow ≥ II after PCI, was defined as RVB recruitment ( Fig. 1 ). Coronary recanalization was performed either by antegrade wire escalation (AWE), antegrade dissection and re-entry (ADR), retrograde wire escalation (RWE), or retrograde dissection and re-entry (RDR). Procedural success was defined as <30% diameter stenosis and TIMI flow grade III.

Invasive coronary angiography of two PCI CTO procedures illustrating right ventricular side branch loss and gain. Panel A shows a completely occluded RCA with one clinically significant RVB. The CTO was successfully crossed using an RDR technique; the concomitant dissection plane resulted in occlusion of the RVB (B). Panel C displays a CTO RCA of a patient with no clinically significant RVBs. However, the restoration of antegrade blood flow after PCI CTO using AWE resulted in recruitment of an RVB (D). PCI; percutaneous coronary intervention, CTO; chronic total occlusion, RCA; right coronary artery, RVB; right ventricular branch, RDR; retrograde dissection re-entry, AWE; antegrade wire escalation.

2.3

CMR protocol and image analysis

CMR was performed on a 1.5-T scanner (Avanto, Siemens, Erlangen, Germany) before and approximately 12 weeks after PCI CTO RCA. Functional imaging was performed using an ECG-gated, balanced steady-state free precession sequence in four-, three-, and two-chamber long-axis and short-axis orientations during mild expiration (typical parameters: TR/TE 3.2/1.5 ms, flip angle ~75°, voxel size 1.4 × 1.4 × 5.0 mm, temporal resolution 35–50 ms).

Cardiac magnetic resonance analysis was performed using dedicated software (qMass v7.6, Medis, Leiden, the Netherlands). CMR images were assessed by two experienced observers (PD and SB) who were blinded to the time point of CMR examinations (baseline versus follow-up) and clinical data. Right ventricle endocardial borders were manually delineated on end diastolic and end systolic cine short-axis images ( Fig. 2 ). Right ventricular end diastolic volume (RVEDV), right ventricular end systolic volume (RVESV), and RVEF were automatically calculated according to endocardial borders.

Cine short-axis CMR images. To determine right ventricular function prior and after PCI CTO, right ventricle endocardial borders were manually delineated on end diastolic (A) and end systolic (B) cine short-axis images. CMR; cardiac magnetic resonance imaging. Other abbreviations as Fig. 1 .

2.4

Statistical analyses

Continuous variables are presented as mean values ± standard deviation (SD), whereas categorical variables are expressed as actual numbers with percentages. Continuous variables of paired data were compared with the paired sample t-test or Wilcoxon test, depending on the distribution pattern, whereas differences between multiple groups were compared with the One-Way ANOVA test for normally distributed data and with the Kruskal Wallis test if there was a non-normal distribution. A level of p < 0.05 was considered significant. Statistical analyses were performed using SPSS software (IBM SPSS Statistics 22.0, Chicago, IL).

3.1

Patient population

Seventy-nine patients who underwent CMR imaging prior to successful PCI CTO RCA between January 2013 and April 2016 were retrospectively identified. Of these, 55 consecutive patients with CMR imaging after successful percutaneous treatment of a CTO RCA were included for analysis, whilst 24 patients had refused a follow-up CMR. There were no adverse cardiac events registered during follow up. One patient was excluded for analysis due to insufficient CMR quality to be able to assess RV function accurately. Fifty-four patients (63 ± 10 years) included in the present study underwent CMR imaging 39 days (interquartile range (IQR): 22–62 days) prior and three months after PCI CTO (median days; 99, IQR: 92–105). Patient characteristics are presented in Table 1 . CTO characteristics and collateral function are shown in Table 2 . J-CTO scores were equally distributed among the 54 CTO lesions with 10% being scored as easy (0), 37% as intermediate (1), 28% as difficult (2), and 25% as very difficult (≥ 3). The majority of patients showed well-functioning collaterals with a CC score of 2 (88%) and a Rentrop grade 3 (88%) on invasive coronary angiography.

Table 1

Baseline patient characteristics.

Characteristics	n (%) or mean ± SD
Male	43 (80)
Age (years)	63 ± 10
BMI	27.3 ± 3.4
CAD risk factors
Family history of CAD	21 (39)
Hypertension	26 (48)
Hypercholesterolemia	20 (37)
Smoking	17 (32)
History of smoking	16 (30)
Diabetes mellitus	10 (19)
Medication
Beta blockers	43 (80)
Anticoagulant	2 (4)
Antiplatelet therapy	47 (87)
Long working nitrates	16 (30)
Calcium antagonist	11 (20)
Statin	41 (76)
Cardiac history
Myocardial infarction	21 (39)
Previous PCI	39 (72)
Previous CABG	5 (9)

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

1. Influence about the flow of distal branch after intervention of the right coronary artery chronic total occlusion
2. Bivalirudin versus heparin in women undergoing percutaneous coronary intervention: A systematic review and meta-analysis of randomized clinical trials
3. Stepwise use of circulatory support devices in a patient refractory to cardiopulmonary resuscitation
4. Out-of-hospital cardiac arrest: Concise review of strategies to improve outcome

Stay updated, free articles. Join our Telegram channel

Join