Comparison of coronary vessel sizing using coronary angiography versus intravascular ultrasound in Egyptian patients

Hany h. Ebaid, Ahmed El-sehili, Hisham Rasheed, Hisham Ammar, Mohamed Mahrous. Comparison of coronary vessel sizing using coronary angiography versus intravascular ultrasound in Egyptian patients. Cardiometry; Issue 20; November 2021; p. 184-189; DOI: 10.18137/cardiometry.2021.20.184189; Available from:

Coronary artery disease (CAD) is one of the major causes of morbidity and mortality worldwide [1]. Coronary revascularization is the most important strategy for coronary artery disease [2]. Quantitative coronary angiography (QCA) has played a crucial role in evaluating interventional techniques [3]. Meanwhile, QCA is subjected to the limitations of two -dimensional imaging, such that it can underestimate disease severity, particularly when positive remodeling has occurred [4]. Recently, intravascular ultrasound (IVUS) is a useful tool during the PCI procedure for providing information on preintervention lesion characteristics, including vulnerable plaques, lesion severity, length, and morphology; on postintervention optimal stent implantation for stent expansion, extension, and apposition; and on possible complications after stent implantation [5]. Mis-sizing of the stent promotes intimal hyperplasia (IH) due to the impact of endothelial shear and intramural stress. Thus, optimal stenting requires correct sizing of the stents, as both oversizing and under-sizing are highly inducive to IH and that predisposes to thrombosis [6]. The use of IVUS guidance in PCI is associated with lower long-term mortality, MI, and repeat revascularization [7].

The objective of this study was to study the discrepancies in coronary vessel sizing between quantitative coronary analysis (QCA) and intravascular ultrasound. That varies according to the vessel evaluated in an Egyptian population sample. To make appropriate adjustments to the size of the vessel during PCI (Percutaneous coronary intervention)

Patients and methods

Inclusion criteria:

Adult patients with stable angina (with evidence of ischemia) or unstable angina.

Exclusion criteria:

Patients not meeting the above inclusion criteria, hemodynamic instability, acute ST-elevation myocardial infarction (STEMI), renal insufficiency (serum creatinine> 1.5 mg/dl), dye allergy, and lesions located in the following sites were excluded; distal segment disease, saphenous vein grafts, and vessel disease of IVUS measurement less than 2.5 mm.

The angiographic assessment was done by both QCA and IVUS:

• (1)    Quantitative Coronary Analysis (QCA):

All coronary angiograms were performed and QCA data was analyzed using the same measurements. The QCA was calculated using (Philips or Siemens Medical System), as far as possible, the same anatomical view for the corresponding vessel to ensure standardization: the right anterior oblique caudal 30°/20° was used for the LCX; the right anterior oblique cranial was used for the LAD and the left anterior oblique cranial view was used for the RCA in each case. The QCA analysis was performed by experienced technicians supervised by an expert physician with identical angulations that best showed the stenosis at its most severe degree with minimal foreshortening and branch overlap. Computer software automatically calculated the luminal diameters. The QCA and IVUS analysis was performed independently by experts.

• (2)    Intravascular ultrasound (IVUS) assessment:

Imaging by Eagle Eye® - Philips Volcano Catheter. Following intracoronary infusion of nitroglycerine (100-200 micrograms) to minimize vasospasm, the rapid exchange IVUS catheter was introduced in the coronary over a standard 0.014” guidewire. Mechanical IVUS systems required infusion of heparinized sa- line to clear air bubbles inside the sheath covering the transducer before inserting the catheter in the guiding catheter. The IVUS catheter was advanced under fluoroscopy guidance approximately 10 mm distal to an anatomical landmark (i.e., side branch) and retracted slowly to straighten the catheter shaft which may have built some slack during insertion to minimize nonuniform rotation distortion (NURD) artifacts [8]. For the guidance of interventional procedures, the worst lesion site and relatively normal adjacent reference sites in end-diastolic frames were selected for analysis [8]. Based on the images depicted during the pullback of the transducer that had been inserted beyond the segment of interest, the lesion was defined as the image slice with the smallest lumen cross-sectional area. In the culprit’s vessels, intravascular ultrasound was done before and after percutaneous coronary intervention.

Statistical analysis

Pre-coded data was entered on the computer using the “Microsoft Office Excel Software” program (365) for Windows. Data was then transferred to the Statistical Package of Social Science Software program, version 25 (SPSS) to be statistically analyzed (IBM Corp., Armonk, NY, USA). Data were summarized using mean, standard deviation, median, and interquartile range for quantitative variables and frequency and percentage for qualitative ones.

Results

There was a statistically significant difference between the luminal diameter of the left main artery measured by QCA in comparison to that by IVUS with differences ranging from -2.1 to 0.5 mm with a median of -0.8 mm [Table 3]. While in LAD the difference between the luminal diameter measured by QCA in comparison to that by IVUS with differences ranging from -1.3 to 0.5 mm with a median of -0.55 mm [Table 4]. Whereas the LCX luminal di-

Table 1

Demographic data and risk factors

	N=69	%
Gender: Male Female	49 20	71 29
Age (year): Mean ± SD Range	54.652 ± 9.7 30 – 71
Diabetes:	38	55.1
Hypertension:	37	53.6
Dyslipidemia:	34	49.3
Smoking:	41	59.4
Precious PCI:	25	36.2
Previous CABG:	15	21.7

Table 2

Distribution of the studied patients according to vessels affected

Number of vessels	N=124	%
Left Main artery (LM)	52	41.9%
Left anterior descending artery (LAD)	46	37.1%
Left circumflex descending artery (LCX)	13	10.5%
Right coronary artery (RCA)	13	10.5%

Table 3

Comparison between the luminal diameter of the left main artery (LM) measured by IVUS and that measured by QCA

Luminal diameter by Test IVUS QCA t p Mean ± SD Range 4.909 ± 0.482 3.6 – 5.8 4.084 ± 0.544 2.3 – 5.4 17.284 <0.001** r (95% CI) 0.507 (-0.147, 0.826) p <0.001** The difference in luminal diameter measured by QCA and IVUS (mm) Median Range -0.8 -2.1, 0.5 t Paired sample t-test r interclass correlation coefficient CI confidence interval **p≤0.001 is statistically highly significant

Table 4

Comparison between the luminal diameter of the left anterior descending artery (LAD) measured by IVUS and that measured by QCA

Luminal diameter by         Test

	IVUS	QCA	t	p
Mean ± SD Range	3.87 ± 0.513 2.6 – 5.1	3.282 ± 0.468 2 – 4.5	13.418	<0.001**
r (95% CI)	0.646 (-0.189, 0.89)		p	<0.001**

The difference in luminal diameter measured by QCA and IVUS (mm)

Median -0.55

Range -1.3, 0.5

t Paired sample t-test r Pearson correlation coefficient CI confidence interval **p≤0.001 is statistically highly significant.

186 | Cardiometry | Issue 20. November 2021

ameter was measured by QCA in comparison to that by IVUS with differences ranging from -1.5 to 0.25 mm with a median of -0.4 mm [Table 5]. Whilst the difference between the luminal diameter of RCA was measured by QCA in comparison to that by IVUS with differences ranging from -0.8 to -0.2 mm with a median of -0.5 mm [Table 6]. So, the discrepancy between luminal diameter measured by IVUS and QCA (median difference in measures by QCA and IVUS in the left main artery, LAD, LCX and RCA were -0.8, -0.55, -0.4, and -0.5 respectively). On pairwise comparison, the difference is significant between the left main artery and each other vessel. Also, there was a statistically significant difference between the studied vessels regarding the presence of difference >0.75 mm between luminal diameter measured by IVUS and QCA (Difference >0.75 mm in the left main artery, LAD, left circumflex and RCA were 55.8%, 21.7%, 30.8%, and 15.4% respectively) [Table 7].

Table 5

Comparison between the luminal diameter of left circumflex artery (LCX) measured by IVUS and that measured by QCA:

Luminal diameter by Test IVUS QCA t p Mean ± SD Range 3.589 ± 0.532 2.8 – 4.7 3.004 ± 0.462 2.3 – 4 5.174 <0.001** r (95% CI) 0.572 (-0.266, 0.876) p 0.012* The difference in luminal diameter measured by QCA and IVUS (mm) Mean ± SD Range -0.4 -1.5, -0.25 t Paired sample t-test r Pearson correlation coefficient CI confidence interval **p≤0.001 is statistically highly significant

Table 6

Comparison between the luminal diameter of right coronary artery (RCA) measured by IVUS and that measured by QCA:

Luminal diameter by         Test

	IVUS	QCA	t	p
Mean ± SD Range	3.539 ± 0.512 2.7 – 4.3	3.062 ± 0.429 2.2 – 3.5	10.458	<0.001**
r (95% CI)	0.739 (-0.101, 0.945)		p	<0.001**

The difference in luminal diameter measured by QCA and IVUS (mm)

Mean ± SD -0.5

Range -0.8, -0.2

t Paired sample t-test r interclass correlation coefficient CI confidence interval **p≤0.001 is statistically highly significant

Table 7

Comparison between difference >0.75 mm between luminal diameters of different arteries measured by IVUS and QCA

Difference	Arteries				Test
	LM	LAD	LCX	RCA	χ2	p
	N=52(%)	N=46(%)	N=13(%)	N=13(%)
≤0.75 mm >0.75 mm	23 (44.2) 29 (55.8)	36 (78.3) 10 (21.7)	9 (69.2) 4 (30.8)	11 (84.6) 2 (15.4)	MC	<0.001**
Difference: Median Range	-0.8¥ -2.1, 0.5	-0.55 -1.3, 0.5	-0.4 -1.5, -0.25	-0.5 -0.8, -0.2	26.179	<0.001**

MC Monte Carlo test KW Kruskal Wallis test **p≤0.001 is statistically highly significant ¥group responsible for significant difference

Additionally, there was a statistically significant difference between the left main and non-left main arteries affected regarding the difference between luminal diameter measured by IVUS and QCA (median difference in the left main artery and non-left main artery were -0.8 and -0.5 respectively). Also, the difference between left main and non-left main arteries affected regarding the presence of difference>0.75 mm between luminal diameter measured by IVUS and QCA (Difference>0.75 mm in the left main artery, and non-left main artery affected was 55.8%, and 22.2% respectively) [Table 8].

Table 8

Comparison between discrepancy >0.75 mm between luminal diameters of left main and non-left main measured by IVUS and QCA:

Discrepancy	Arteries		Test
	Left main	Non-left main	χ2	p
	N=52(%)	N=72 (%)
≤0.75 mm >0.75 mm	23 (44.2) 29 (55.8)	56 (77.8) 16 (22.2)	14.697	<0.001**
Difference: Median Range	-0.8 -2.1, 0.5	-0.5 -1.5, 0.5	-5.062	<0.001**

χ² Chi-square test Z Mann Whitney test

Discussion

The current study involved 69 patients who were selected from those referred to coronary elective coronary angiography. Their gender, risk factors, laboratory data, and angiographic results were collected and statistically analyzed. In our study, we used QCA and IVUS to assess the luminal diameter of each coronary vessel to reveal differences between both.

In our study, the studied patients were 71% males with a mean age of 54.7 ± 9.7 years. The main risk factors were smoking (59.4%), systemic hypertension (53.6%), diabetes mellitus (55.1%), dyslipidemia (49.3%) with a history of PCI (36.2 %), and CABG (21.7 %). This is consistent with Goel et al. study [9] which was included (87%) males with a mean age of 57.5+9.8 years with systemic hypertension (53%), dyslipidemia (46.1%), diabetes mellitus (34%), and smoking (32%) as risk factors. In addition, De la Torre Hernandez et al. study [10] included (76%) males with a mean age of 66.5 ± 11.0 years with systemic hypertension (63.1%), dyslipidemia (65.9%), diabetes mellitus (35.8%), and smoking (25.1%) as risk factors with history of PCI (29.6 %) and CABG (2.8%). Furthermore, Jen-Hsiang Wang et al. study [11] enrolled (80%) males with mean age 68±8 years, and risk factors of smoking (55.2%), systemic hypertension (59 %), diabetes mellitus (54%), dyslipidemia (46.2%) with a history of PCI (25.3 %) and CABG (5.6 %). Moreover, Fernandes et al. study[12] studied patients were (54%) males with an average age of 61 ± 13 years, (48%) had dyslipidemia, (27%) were smokers, (62%) had systemic hypertension, and (17%) had diabetes.

Our study studied sixty-nine patients with lesions involved Left main in 52 cases (41.9%), LAD in 46 cases (37.1%), followed by LCX in 13 cases (10.5%), and RCA in 13 cases (10.5%). And the discrepancy between luminal diameter measured by IVUS and QCA was calculated. Left main luminal diameter was 4.9 ± 0.48 by IVUS versus 4.1 ± 0.5 by QCA, LAD luminal diameter was 3.87 ± 0.5 by IVUS versus 3.3 ± 0.46 by QCA, LCX luminal diameter was 3.6 ± 0.5 by IVUS versus 3.0 ± 0.46 by QCA and RCA luminal diameter was 3.5 ± 0.5 by IVUS versus 3.0 ± 0.4 by QCA. The median differences in measures of QCA and IVUS in the left main artery, LAD, LCX, and RCA were -0.8, -0.55, -0.4, and -0.5 respectively. And the presence of difference >0.75 mm between luminal diameter measured by IVUS and QCA (Difference >0.75 mm in the left main artery, LAD, LCX, and RCA was 55.8%, 21.7%, 30.8%, and 15.4% respectively). Similarly, in Goel et al. study [9] assessed 186 cases of Left main with luminal diameter by IVUS was 4.33 ± 0.32 versus QCA which was 3.89 ± 0.25. And the assessed 177 cases of LAD with luminal diameter by IVUS was 3.61 ± 0.21 versus QCA diameter was 3.36 ± 0.28. And the assessed 44 cases of LCX with luminal diameter by IVUS was 3.31 ± 0.16 versus QCA diameter was 2.85 ± 0.27. Also, De la Torre Hernandez et al. study [10] in which 179 cases of the left main lesion were assessed and the luminal diameter by IVUS was 4.2 ± 0.7 versus QCA diameter was 3.9 ± 0.8. In addition, Jen-Hsiang Wang et al. study [11] studied LAD lesions of 30 patients, The mean reference diameter of the LAD proximal segment by QCA was 3.21 mm, and IVUS was 3.40 mm. The mean reference diameter of the LAD middle segment by QCA was 3.00 mm and IVUS was 3.28 mm. Moreover, Fernandes et al. study [12] studied 56 patients with a total of 63 stenotic coronary lesions and assessment of reference segment luminal diameter, which was 2.83 ± 0.56 mm by angiography versus 3.45 ± 0.69 mm by IVUS.

On the other hand, Takagi et al. study [13] enrolled 427 consecutive patients, mainly males’ patients (93.9%) with a mean age of 63.75± 10.0 years with systemic hypertension (56.8%), dyslipidemia (59.9%), diabetes mellitus (19.4%), smoking (26.2%), previous CABG (12.6%) and previous PCI (48%) as risk factors. They underwent PCI with intravascular ultrasound (IVUS)-guidance. The minimum stent diameter (MSD) was measured using QCA (MSDQCA) and IVUS (MS-DIVUS) analysis. The lesions were assessed were 162 lesions in LAD, 70 in LCX, and 77 in RCA. The mean MSDQCA and MSDIVUS were 3.04 ± 0.49 mm and 2.68 ± 0.47 mm, respectively. And concluded that the MSDQCA is more likely to overestimate in the LCX than in the LAD, particularly when the MSDIVUS is 2.5 mm. Therefore, it is recommended that be less aggressive in oversizing balloons and stents based on QCA for LCX or small vessel intervention.

There was a difference > 0.75 mm between the luminal diameter measured by IVUS and QCA (Difference > 0.75 mm in the left main artery, LAD, LCX, and RCA were 55.8%, 21.7%, 30.8%, and 15.4% respective- 188 | Cardiometry | Issue 20. November 2021

ly). In other words, there was a presence of a difference > 0.75 mm between the luminal diameters measured by IVUS and QCA (Difference > 0.75 mm in the left main artery and non-left main artery affected were 55.8%, and 22.2% respectively). On the contrary, Takagi et al. study13 found that the difference between MSDQCA and MSDIVUS of > 0.75 mm was more frequently observed in the LCX rather than in the LAD (7.4% in the LAD vs. 24.3% in the LCX, p = 0.001). The discrepancy between the MSDQCA and MSDIVUS for the LCX was larger than for the LAD and tended to be larger than for the RCA (13.3% vs. 18.5%, p = 0.05 and 18.5% vs. 14.5%, p = 0.17). Which could support the strategy to downsize devices in the LCX to reduce the occurrence of coronary dissection and rupture.

Limitations

Our study has some limitations. The size of the population sample was relatively small and not randomized. Larger, multi-centric studies should be performed to confirm our results. Our study population had only 29% females, thereby limiting the generalizability of the results. The measurements were not validated by an external core laboratory, which could have allowed some intraobserver bias. In addition, further research would be required to validate our results.

Conclusion

Coronary lesions were underestimated by QCA in comparison to IVUS regarding luminal diameter (Media to media), especially the left main (LM).

Statement on ethical issues

Research involving people and/or animals is in full compliance with current national and international ethical standards.

Funding

This research did not receive any specific grants from funding agencies in the public, commercial, or not-for-profit sectors.

Conflict of interest

None declared.

Author contribution

The authors contributed equally to the study. The authors read the ICMJE criteria for authorship and approved the final manuscript.