The goal of this study aim to accurately size the IABP size for patients. The main questions it aims to answer are:

• Are patients's height, jugular notch to transpyloric plane distance and distance from the carina to the upper part of the first lumbar vertebra (measured by chest X-ray) are a good surrogate for IABP sizing?
• Is the distance obtained during a transfemoral artery catheterization a reliable way to size the IABP? Researchers will enroll patient who have had previous CT that include thoracic aorta to celiac trunk who will undergo transfemoral angiography.
• All patients that researcher enrolled will undergo transfemoral angiography, during which the researchers will measure the vessel distance using a wire after the procedure end.
• Researchers will measure the height weight, jugular notch to transpyloric plane distance, CXR distance from carina to upper border of L1 and the distance from aorta at subclavian level to celiac trunk from CT.
• Researchers will find the correlation between of each measurement to the distance from aorta at subclavian level to celiac trunk from CT (considered the standard measure).

Background:

• Intra-aortic balloon pumps (IABP) are commonly used as mechanical circulatory support in patient with cariogenic shock.
• Proper sizing of IABP is critical, critical, with the balloon typically extending from the left subclavian artery to the celiac axis, and occupying 90-95% of the aorta's diameter during each cycle.
• Manufacturers usually recommend balloon sizes based on patient height. However, previous studies suggest that the accuracy of these recommendations varies. One study found that while chest X-ray (CXR) confirmed correct balloon positioning in 96.8% of cases, only 38.1% were accurately positioned based on CT scans.
• Malposition of the balloon, such as blocking the renal or mesenteric arteries, may lead to complications like renal or intra-abdominal ischemia
• Cadaveric studies have suggested that the distance from the jugular notch to the transpyloric plane correlates more strongly with the subclavian-to-celiac artery distance than height alone
• A Chinese study attempted to predict the left subclavian artery to celiac trunk distance using a combination of height, body mass index (BMI), and age
• In this study, investigators want to find the better way in sizing IABP balloon. Investigators with use the height, age, weight, jugular notch to transpyloric plane distance, distance from the carina to the upper part of the first lumbar vertebra (measured by chest X-ray) and length of the vessel measured during transfemoral angiography compare with distance of the vessel measure during CT-scan.

Outcome

• Investigators will find the correlation between height, jugular notch to transpyloric plane distance, wire pull out distance from aortic knob to L1 in angiographic study and distance of left subclavian artery to celiac trunk measure from CT aorta using Pearson Correlation or Spearman rank statistics.
• Referencing previous studies

The correlation coefficient between height and the distance to the LCA-celiac trunk was 0.369 , and the correlation coefficient between height and the distance to the LCA-renal artery was 0.579 (Igari T. The length of the aorta from the subclavian artery to the renal artery based on computed tomographic measurements in Japanese adults. Journal of Artificial Organs. 2006;9:267-70.). The researcher chose to use the lower correlation coefficient of 0.369 for calculating sample size to achieve a maximum sample size.Using the formula for calculating sample size for correlation coefficient testing, with a standard value of 1.96 set at a significance level of 5% and a power of 80%, the sample size was calculated as follows:

• Fisher's Z Transformation from formula = = 1/2 ln((1+(0.369))/(1-(0.369)))= 0.387 Calculate sample size by n= ((1.96+0.84)/(0.387))^2+3 n = 56 Sample size from this calculation is 56, it was determined that an additional sample size of 56 participants is needed, with a further increase of 20% to account for potential data loss, resulting in an additional 12 participants, totaling 68 individuals. Therefore, the sample size used in this study is 68 participants Recruitments - Investigators will review patients scheduled for angiography to determine if they have had a CT chest scan that includes the celiac trunk and are eligible for the study.

Inclusion criteria are

1. Patient age ≥ 18 years old
2. Patients had obtained CT scan of chest with upper abdomen with celiac trunk visualize within 1 year from the day of transfemoral angiography
3. Patients had who will undergo transfemoral angiography as clinical indicated
4. Patients had obtained Chest X-ray within 1 year from the day of transfemoral angiography Exclusion criteria are

1. Patient with limb amputation 2. Patient with known aortic abnormalities such as aortic aneurysm, aortic dissection Study procedure

• Before the patient's arrival at the catheterization lab, the investigator will seek their consent to participate in the study.
• Patients will be informed that their treatment will proceed as usual, with the only additional step being a request for the procedure operator to measure the pullback wire distance at the end of the procedure. This step will result in slightly more radiation exposure but will take less than one minute to complete and does not increase the procedural risk.
• If the operator determines that the patient is unstable, the measurement will not be performed. Patients who choose not to participate will still receive their standard treatment without any changes.
• Other measurements such as height weight will be collected per Cath lab protocol.
• The measurement of jugular notch to transpyloric plane distance will be collect at the recovery ward.

Inclusion Criteria:

• Patients had obtained CT scan of chest with upper abdomen with celiac trunk visualize within 1 year from the day of transfemoral angiography
• Patients had who will undergo transfemoral angiography as clinical indicated
• Patients had obtained Chest X-ray within 1 year from the day of transfemoral angiography

Exclusion Criteria:

• Patient with limb amputation
• Patient with known aortic abnormalities such as aortic aneurysm, aortic dissection

Patients undergoing transfemoral angiography at Siriraj cauterization lab.

2 years after the study end

Data sharing upon reasonable request.