Figure 1
Study flow diagram.
Table 1
Characteristics of patients as per coronary angiography findings.
| CHARACTERISTICS | TOTAL n = 2984 n(%) | NON-OBSTRUCTIVE CORONARIES n = 711(24.0) | MODERATELY OR SEVERELY OBSTRUCTIVE CORONARIES n = 2273(76.0) | p-VALUE |
|---|---|---|---|---|
| Age* | 57.9 ± 9.7 | 55.2 ± 10.2 | 58.8 ± 9.4 | <0.001 |
| Age <50 | 567(19) | 202(28.4) | 365(16.1) | <0.001 |
| Women | 701(23.5) | 284(39.9) | 417(18.3) | <0.001 |
| BMI*~ | 27.8 ± 4.9 | 28.5 ± 6.0 | 27.6 ± 4.5 | NS+ |
| Prior heart failure | 115(3.9) | 41(5.8) | 74(3.3) | 0.01 |
| Dyslipidemia | 1052(35.3) | 203(28.6) | 849(37.4) | <0.001 |
| Hypertension | 2054(68.8) | 467(65.7) | 1587(69.8) | NS |
| Family history of premature CAD | 501(16.8) | 108(15.2) | 393(17.3) | NS |
| Diabetes mellitus | 1569(52.6) | 300(42.2) | 1269(55.8) | <0.001 |
| Smoker | 433(14.5) | 77(10.8) | 356(15.7) | 0.003 |
| Indication | ||||
| Positive stress test | 1396(46.8) | 184(25.8) | 1212(53.3) | <0.001 |
| Heart failure evaluation | 697(23.4) | 303(42.6) | 394(17.3) | |
| Angina | 774(25.9) | 167(23.4) | 607(26.8) | |
| Other | 117(3.9) | 57(8.2) | 60(2.6) | |
| Symptoms | ||||
| Typical angina | 1898(63.5) | 291(40.9) | 1,607(70.7) | <0.001 |
| Atypical angina/unlikely angina | 313(10.5) | 145(20.4) | 168(7.4) | |
| Asymptomatic | 773(25.9) | 275(38.7) | 498(21.9) | |
| Modified Framingham risk score | ||||
| Low | 950(31.8) | 344(48.4) | 606(26.6) | <0.001 |
| Intermediate | 1,268(42.5) | 258(36.3) | 1,010(44.4) | |
| High | 766(25.7) | 109(15.3) | 657(29.0) | |
| Operators as per annual volume | ||||
| >400 | 1397(46.8) | 278(39.1) | 1,119(49.2) | 0.001 |
| 100–400 | 1,170(39.2) | 313(44.0) | 857(37.7) | |
| <100 | 417(14.0) | 120(16.9) | 297(13.1) |
[i] * Mean ± standard deviation.
~ BMI is weight in kg divided by the square of height in meters Chi-sq test used to determine p-values.
+ Independent sample T-test used to determine the p-value CAD: Coronary artery disease, NS: Nonsignficant.
Figure 2
CAG findings as per NIT results.
Table 2
Findings of Non-invasive testing as per coronary angiography findings (n = 1462).
| N(%) | NON-OBSTRUCTIVE CORONARIES n = 711(24.0) | MODERATELY OR SEVERELY OBSTRUCTIVE CORONARIES n = 2273(76.0) | p-VALUE | |
|---|---|---|---|---|
| No NIT | 1522(51) | 497(32.7) | 1025(67.3) | <0.001 |
| NIT | 1462(49) | 214(14.6) | 1248(85.4) | |
| Type of NIT | ||||
| ETT | 452(30.9) | 68(15) | 384(85) | |
| Low risk | 14(3.1) | 7(50) | 7(50) | |
| Intermediate | 164(36.3) | 32(19.5) | 132(80.5) | |
| High risk | 265(58.6) | 34(12.8) | 231(87.2) | |
| SE | 175(11.9) | 46(26.3) | 129(73.7) | |
| Low risk | 2(1.1) | 1(50) | 1(50) | <0.001 |
| Intermediate | 50(28.6) | 25(50) | 25(50) | |
| High risk | 113(64.6) | 16(14.2) | 97(85.8) | |
| SPECT-MPI | 796(54.5) | 94(11.8) | 702(88.2) | |
| Low risk | 17(2.1) | 8(47.1) | 9(52.9) | |
| Intermediate | 189(23.7) | 36(19.1) | 153(80.9) | |
| High risk | 540(67.8) | 28(5.2) | 512(94.8) | |
| CCTA | 39(2.7) | 6(15.4) | 33(84.6) | |
| Results of NIT | ||||
| Positive | 1396(95.5) | 184(13.2) | 1212(86.8) | <0.001 |
| Negative | 48(3.3) | 23(47.9) | 25(52.1) | |
| Indeterminate | 18(1.2) | 7(38.9) | 11(61.1) | |
| Risk stratification of NIT | ||||
| Low | 33(2.4) | 15(45.5) | 18(54.5) | <0.001 |
| Intermediate | 403(29.5) | 89(22.1) | 314(77.9) | |
| High | 918(67.3) | 76(8.3) | 842(91.7) | |
| Unavailable | 10(0.7) | 2(20) | 8(80) |
[i] * The percentages in columns of non-obstructive coronaries and moderately or severely obstructive coronaries are row percentages to provide a % of moderately or severely and non-obstructive coronaries as per non-invasive test finding.
CCTA: Cardiac computed tomography angiography, ETT: Standard exercise test, NIT: non-invasive testing, SE: Stress echocardiogram, SPECT-MPI: Single photon emission computed tomography-Myocardial perfusion imaging.
Figure 3
Bull’s eye diagram depicting CAG as per AUC stratification.
Table 3
Predictors of non-obstructive coronaries in patients undergoing elective coronary angiography.
| CHARACTERISTICS | CRUDE PREVALENCE RATIOS (95% CI) | ADJUSTED PREVALENCE RATIOS (95% CI) | p-VALUE |
|---|---|---|---|
| Age < 50 | 1.7(1.4–2) | 1.3(1.0–1.5) | 0.03 |
| Women | 2.1(1.9–2.5) | 1.8(1.5–2.1) | <0.001 |
| Modified Framingham risk score | |||
| Low | 2.5(2.1–3.1) | 1.9(1.5–2.5) | 0.02 |
| Intermediate | 1.4(1.1–1.7) | 1.3(1.0–1.6) | |
| Appropriate use criteria | |||
| Inappropriate | 3.6(2.2–5.7) | 2.7(1.6–4.3) | 0.02 |
| Uncertain | 1.3(1.1–1.6) | 1.3(1.1–1.6) | |
| Not rated | 1.9(1.1–3.3) | 1.4(0.8–2.5) | |
| No NIT testing or positive low-risk NIT findings | 2.6(2.2–3.1) | 1.8(1.5–2.2) | <0.001 |
| Indication for CAG | |||
| Heart failure/LV dysfunction | 2.4(2.1–2.8) | 1.7(1.4–2.0) | <0.001 |
[i] * Variables including prior heart failure, diabetes, dyslipidemia, smoking history, CAD presentation, and operator as per annual volume were not found significant in the multivariable model.
** Older age ≥ 50, men, high MFRS, appropriate AUC, positive intermediate/high-risk NIT, and indications other than heart failure/LV dysfunction were taken as reference.
CAG: coronary angiography, LV dysfunction: left ventricular dysfunction, NIT: non-invasive testing.
Figure 4
Temporal trends of inclusion of elective coronary angiography patients, NOC and NIT during 2012–2020.
Figure 5
Temporal trends for indications of elective CAG during 2012–2020.